THE  TEACHER'S  MANUAL 


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ANATOMY 


PHYSIOLOGY 


AND  EFFECTS  OF 


ALCOHOL  fin D 


RASSWEILER 


LIBR 
G 


LIBRARY 

OF   THK 


UNIVERSITY  OF  CALIFORNIA. 


GIKT  OK 


Received 

on  No.     ^  ^  $/    .    Class  No. 


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THE  TEACHERS'  MANUAL 


PUPILS'  TEXT  BOOK 


Anatomy,  Physiology  and  Hygiene. 

INCLUDING  THE  EFFECTS   OF 

ALCOHOL  AND  NARCOTICS  UPON 
THE  HUMAN  SYSTEM, 

DESIGNED   TO  ACCOMPANY 

THE  TEACHERS'  ANATOMICAL  AID 


IJY 


PROF.  J.  K.  RASSWEILER,  A.  M. 


PUBLISHED  BY 

CENTRAL  SCHOOL  SUPPLY  HOUSE, 
CHICAGO,  ILLINOIS. 


BIOLOGY 

LIBRARY 

G 


Entered  according  to  Act  of  Congress,  in  the  year  1889, 

BY  CENTRAL  SCHOOL  SUPPLY  HOUSE, 
in  the  office  of  Ihe  Librarian  of  Congress,  at  Washington,  D.  C 


PREFACE. 


This  book  is  intended  to  go  into  the  schools  of 
the  country  as  a  companion  to  the  "  TEACHERS'  ANA- 
TOMICAL AID,"  which  is  supposed  to  be  before  the 
class  during  every  exercise  or  recitation  in  Physi- 
ology, and  to  which  the  illustrative  references,  found 
throughout  these  pages,  relate. 

To  the  teacher  who  gives  oral  lessons  in  Physi- 
ology, by  the  use  of  the  Aid,  this  volume  offers 
assistance  in  presenting  the  truths  of  the  science  in 
proper  order,  plain  language,  and  with  many  illus- 
trations gathered  within  the  range  of  the  pupils' 
observation  and  experience.  Thus,  even  inexperi- 
enced teachers  are  furnished  with  methods  and 
material  to  conduct  a  well-arranged  course  of  daily 
drills  on  a  subject  of  surpassing  importance  and 
interest. 

To  the  teacher  who  conducts  a  recitation,  with  the 
use  of  the  Aid,  this  work  offers  guidance  in  point- 
ing out,  precisely,  by  its  frequent  references,  those 
parts  or  features  on  the  plates  or  manikin  sections, 
which  illustrate  any  topic  in  hand,  as  found  in  the 
current  text-books  on  Physiology. 

While  this  book  is  thus  intended  to  be  helpful  to 
(1) 


2  PREFACE. 

teachers  of  all  grades  of  experience,  it  is,  at  the 
same  time,  adapted  for  use  as  a  text-book  for  ele- 
mentary classes.  The  practical  results  which  may 
be  obtained  from  such  a  use  of  it,  in  connection 
with  the  Anatomical  Aid,  will  be  found  to  be  more 
satisfactory  than  those  which  can  be  attained  by  any 
other  method  of  instruction  in  the  elements  of 
Physiology. 

When  used  as  a  text-book  with  the  Aid,  the  latter 
should  be  made  conveniently  accessible  to  the 
pupils.  This  can  easily  be  done  in  any  school- 
room. The  objection  that  the  pupils  will  injure  the 
charts  by  handling  them,  is  a  mischievous  notion. 
They  are  entitled  to  such  privileges.  If  well  and 
kindly  advised,  they  will  handle  them  properly  and 
will  take  pride  in  carefully  preserving  them  from 
injury. 


TABLE  OF  CONTENTS. 


THE  SKELETON. 

PAGE. 

Bones— Like  the  Framework  of  a  House— Number  of  Bones— Shape—  * 
Structure— How  United— Bound  Together  by  Ligaments— Uses 
of  the  Bones— Division  of  the  Skeleton— Table  of  the  Skeleton— 
Bones  of  the  Head— The  Skull— The  Face— Bones  of  the  Trunk— 
The  Spinal  Column— Vertebrae— The  Chest— The  Pelvis— Bones  of 
the  Upper  Extremities— The  Shoulder— The  Arm— "Bones  of  the 
Lower  Extremities— T\\Q  Thigh— Lower  Leg  and  Foot— Health  of 
the  Bones— Outline— Questions 5 

THE  MUSCULAR- SYSTEM. 

The  Muscles— Number  and  Structure  of  Muscles— Tendons— Use  of 
the  Muscles — Language  of  the  Muscles — Two  Kinds  of  Muscular 
Action— How  Muscles  Act— Antagonists  or  Counter  Muscles- 
Some  Prominent  Muscles  and  Their  Names— Health  of  the  Mus- 
cles— Outline — Questions 19 

THE  NERVOUS  SYSTEM. 

The  Brain  -  Structure— Protection  to  the  Brain— Divisions  of  the 
Brain — Hemispheres — Work  of  the  Cerebrum — Work  of  the  Cere- 
bellum—The Spinal  Cord— The  Nerves— iNervous  Action— Reflex 
Nervous  Action — Sympathetic  Nervous  Action — Health  of  the  Ner- 
vous System—  Outline— Questions 29 

THE  SPECIAL  SENSES. 

Nerves  of  Common  Sensation— Nerves  of  Special  Sensation— The 
Eye— Protection  of  the  Eye— Tear  Apparatus— The  White  Coat  of 
the  Eyeball— The  Black  Coat— The  Nervous  Coat-Thp  Humors  of 
the  Eye— 7  he  Kar-The  Nerve  of  Hearing— The  Outer  Kar— The 
Middle  Ear -The  Inner  Ear— How  We  Hear—  The  Sense  of  Smell- 
How  We  Perceive  Odors— The  Sense  of  Taste— The  Tongue— How 
We  Perceive  Taste^-  Outline— Questions 41 

THE  CIRCULATORY  SYSTEM. 

Organs  of  the  Circulatory  System— The  Heart— The  Arteries— The 
Veins— The  Capillaries— Blood  Change  in  the  Capillaries -The 
Course  of  the  Blood— Three  Divisions  of  the  Circulation— Inter- 
esting Facts— Health  of  the  Circulatory  System— Outline— Ques- 
tions    54 

THE  RESPIRATORY  SYSTEM. 

Structure  of  the  Lungs— Use  of  the  Lungs— Breathing— How  We 
Breath— Chief  Breathing  Muscles— Pleura— Health  of  the  Respira- 
tory Organs — Exercise — Impurities  of  the  Breath — Ventilation — 
The  Voice— The  Larynx— An  Experiment— Speech— Outline- 
Questions 62 


4:  CONTENTS. 

THE  DIGESTIVE  SYSTEM. 

Body—  Building  from  Blood— Aid  of  the  Muscular  System— Work  of 
the  Teeth -Number  of  Teeth— Structure  of  a  Tooth— Work  of  the 
_  Salivary  Glands— Work  of  the  Pharynx  and  Oesophagus— Work  of 
the  Stomach— Use  of  the  Gastric  Juice— Work  of  the  Pylorus- 
Work  of  the  Liver— Work  of  the  Pancreas— Health  of  the  Diges- 
tive System  -Eating  too  Fast— Eating  too  Much— Eating  too  Fre- 
quently-Eating  Indigestible  Food— Exercise—  Outline— Questions.  71 

THE  ABSORPTIVE  SYSTEM. 

Absorption— Intestinal  Villi— Two  classes  of  Absorbents  in  theViili— 
Veins  in  the  Villi  -  Portal  Circulation— The  Second  Route— Lac- 
teals  in  the  Villi— Chyliferous  Vessels  and  Lymphatic  Glands- 
Thoracic  Duct— What  Has  Been  Done— Assimilation— Recapitula- 
tion—The Lymphatic  Vessels— Lymph— Origin  of  Lymph— The 
Lymphatics— The  Lymphatics  a  System  of  Drainage— The  Lym- 
phatic Glands— The  Lacteals,  a  part  of  the  Lymphatics— Lympha- 
tics Om  pared  with  the  Blood  Vessels— Other  Functions  of  the 
Lymphatics  -Suggestions  to  the  Teacher— Outline— Questions 87 

THE  EXCRETORY  SYSTEM. 

Excretory  Organs— Impurities  .Thrown  Off  by  the  Lungs— Carbon  Di- 
oxide— Carbon  Acid  Test— Test  of  the  Breath— Watery  Vapor  Ex- 
haled— The  Liver—  As  an  Excretor"  Organ— The  Kidneys— Work 
of  the  Kidneys— The  Kidneys  at  Work — Difference  Between  the 
Secretions  of  the  Liver  and  Kidneys 93 

MICROSCOPIC  LESSON. 

Its  Purpose— The  Microscope  as  an  Aid  in  Physiology— Microscopic 
Structure  of  the  Arteries— Ot  the  Veins— Of  the  Capillaries— Of 
the  Mucus  Membrane— Of  the  Looped  Capillaries  of  the  Skin— Of 
the  Intestinal  Villi -Of  the  Air  Cells  of  the  Lungs— Capillaries 
of  the  Parotid  Gland,  Brain  and  Cellular  Tissue— Of  the  Elastic 
Tissues.  Muscular  Fiber  and  Bone  Corpuscles — Of  Voluntary  Mus- 
cles—Of  the  Glands  of  the  Stomach— Of  the  Nerve  Fibers  of  the 
Brain— Of  the  Hepatic  Vein— Of  the  Kidney  Structure- Of  Red 
Blood  Corpuscles— Of  Tendinous  Fiber— Adipose  Tissue— Epithe- 
lial Cells— Cells  of  Epidermis— Pigment  from  Choroid  Coat  of 
Jiye— Other  Views 98 

EFFECTS  OF  ALCOHOL. 

Value  of  a  Sound  Body— Abuse  of  the  Body— Strong  Drink— Alcohol 
and  What  is  It!  What  is  Its  Origin— How  is  It  Done— Fermenta- 
tion—Acetous  Fermentation — Beer  from  Barley— Distillation — 
Two  Classes  of  Strong  Drink— A  Healthy  Stomach— Inflamma- 
tion -Uloeration— Last  Stages  of  Alcohol  Poisoning— Alcohol 
and  the  Liver— The  Result— Alcohol  and  the  Kidneys- Effects  on 
the  Brain— The  Brain  the  geat  of  the  Mind— Consequences  Alco- 
holic Softening  of  the  Brain— Delirium  Tremens— Effect  on  the 
Nerves— Different  Effects  of  Intoxicants  upon  the  Heart— Synop- 
sis—What  It  Will  not  Do 106 

TOBACCO  AND  ITS  EFFECTS. 

Tobacco  is  a  Poison— Its  Effects  upon  the  Young— Cigarette  Smoking— 
An  Experiment— The  Respiratory  Organs— How  Affected -Con- 
clusion    119 


OF  THB 

UNIVERSITY 


THE  SKELETON. 


BONES. 

Like  the  The  framework  of  the  body  is  com- 
r/a^ouse1*  Posed  °^  bones  and  ligaments.  It  is 
called  the  skeleton.  What  beams,  joists 
and  rafters  are  to  a  house,  bones  are  to  the  body. 
As  each  timber  in  the  framework  of  a  building  is 
fitted  for  its  own  particular  place  and  purpose,  so 
each  one  of  the  bones  of  the  body  has  its  own  place 
and  is  in  every  way  precisely  adapted,  in  shape  and 
•strength,  for  a  special  use. 

There  are  two  hundred  and  eight  bones 
Number  jn  ^Q  gkeieton.  This  does  not  include 

oi  Bones. 

the  teeth,  for  they  are  really  not  a 
part  of  the  skeleton.  Thirty-four  of  the  bones  of 
the  body  are  single — only  one  of  the  same  kind. 
Besides  these,  there  are  eighty-seven  pairs,  the  two 
bones  of  each  pair  being  alike — one  on  each  side  of 
the  body. 

The   skeleton  plate  shows  that  the   bones 

Shape.  ...-„  .  _. 

are    very    different    in    shape.      Some    are 
long,    like   this    (leg    bone),   for  example.     Others 

(5) 


6  ELEMENTARY  PHYSIOLOGY. 

are  nearly  round,  like  these  bones  of  the  wrist. 
Some  are  quite  flat,  like  this  large,  spreading  bone 
at  the  shoulder  (16),  or  these  broad  bones  in  the 
lower  part  of  the  main  body  (3). 
structure  ^~^6  bones  are  very  hard  and  strong. 
"Hard  as  a  bone"  is  a  familiar  compar- 
ison. We  shall  not  be  surprised  at  their  hardness 
aod  strength  when  we  shall  have  learned  what  im- 
portant uses  they  serve  in  the  body.  There  are  two 
kinds  of  material  in  the  structure  of  a  bone.  One 
part  is  called  animal  matter  and  the  other  is  called 
mineral  matter.  If  the  bone  were  composed  of 
animal  matter  alone,  it  would  bear  no  pressure  and 
keep  no  permanent  shape.  If  it  were  made  entirely 
of  mineral  matter  it  would  be  too  brittle,  and  conse- 
quently would  break  very  easily.  So  these  two  kinds 
of  material  'are  united  together  in  such  a  way  as  to 
secure  strength  without  too  great  brittleness.  In 
childhood  the  bones  are  not  easily  broken.  This  is 
because  in  early  life  they  contain  about  twice  as 
much  animal  matter  as  mineral  matter.  What  a  wise 
protection  against  the  "bumps"  and  "tumbles"  of 
the  little  ones.  In  middle  life  the  two  kinds  of 
material  are  more  nearly  equally  divided.  In  old 
age,  however,  the  bones  are  very  brittle,  because, 
then,  there  is  about  twice  as  much  mineral  matter  as 
animal  matter  in  their  structure. 

It  is  an  easy  and  interesting  experiment  to  sepa- 
rate these  two  kinds  of  bone  material .  Throw  a  flat 
bone,  or  piece  of  bone,  into  the  fire.  After  a  while 


THE  SKELETON.  7 

you  will  find  a  part  of  it,  like  a  cinder,  among  the 
ashes.  This  is  the  mineral  part.  The  fire  has 
burned  out  the  animal  matter.  Take  the  "drum- 
stick" bone  of  a  chicken  and  place  it  in  a  bottle  con- 
taining a  mixture  made  by  filling  the  bottle  half  full 
of  water  and  adding  about  half  as  much  muriatic 
acid — a  common  drug  which  you  can  get  for  a  trifle 
at  the  nearest  drug  store.  This  will  take  out  the 
mineral  matter  from  the  bone  and  leave  the  animal 
matter.  The  mineral  matter  which  you  took  from 
the  fire  was  brittle  or  crumbling.  The  animal 
matter,  when  taken  from  the  acid,  is  gluey  and  can 
be  wound,  like  a  cord,  about  the  finger.  The  broad 
or  flat  bones,  like  those  of  the  head,  are  not  entirely 
solid.  Between  the  two  outside  layers  of  such  a  bone 
there  is  a  layer  of  spongy-like  material.  These 
three  layers  of  structure  in  a  flat  bone  can  be  clearly 
seen  hy  looking  at  the  edge  of  such  a  bone  which 
has  been  sawed  through. 

The  long  bones  are  generally  hollow  and  contain 
a  substance  called  marrow.  At  the  ends  they  are 
usually  thicker  and  more  spongy.  This  serves  to 
break  the  force  or  shock  of  heavy  stepping  or  jump- 
ing with  the  lower  limbs,  or  a  hard  stroke  with  the 
arm.  The  ends  of  the  long  bones  are  also  covered 
with  a  smooth,  white  substance  called  cartilage. 
This  aids  in  giving  the  bone  an  easy  motion  at  the 
joint  where  it  is  united  to  another  bone. 


8  ELEMENTARY  PHYSIOLOGY. 

The   bones  are    united   to   each    other   in 
United,    different   ways.       Those    which    are    quite 

movable  are  connected  by  joints.  Some 
of  these  are  called  hinge-joints  because  they  work 
like  the  hinge  of  a  door.  These  (arm)  bones 
which  meet  at  the  elbow  are  hinge-jointed.  Eaise 
and  lower  your  forearm  and  notice  particularly  how 
the  joint  acts.  The  joints  in  the  fingers  and  the 
knee  are  also  hinge-joints.  Another  kind  is  called 
the  ball  and  socket  joint,  where  the  round  end  of  one 
bone  moves  in  a  hollow  place  of  another.  Here  (a) 
at  the  hip  is  a  good  example  of  a  ball  and  socket 
joint,  where  the  round  head  of  this  large  upper  bone 
of  the  leg  moves  in  a  deep  hollow  of  this  lower  bone 
of  the  main  body.  The  bones  of  the  head  meet  each 
other  with  jagged  edges  forming  a  seam-like  junc- 
tion called  a  suture.  One  of  these  is  clearly  shown 
on  this  skeleton  (12).  Between  the  bones  of  the 
back  are  placed  cushions  of  cartilage.  This  is  a 
substance  softer  than  bone  and  quite  elastic,  like 
rubber.  This  cushion  arrangement  between  the 
bones  of  the  back,  is  nicely  shown  on  this  plate. 
(Refer  to  cartilages  between  lumbar  vertebrae.) 

The  bones  are  bound  to  one  another 

Bound  To-  .  _ 

Bother  by  by  ligaments.  These  are  very  strong 
Ligament*.  and  hol(j  foe  bones  firmly  in  position. 
Some  of  these  stout  bands  or  ligaments  are  shown  on 
this  plate.  Here  (XVI)  are  the  ligaments  which 
bind  together  the  bones  of  the  hip.  These  (XXV, 
XXVI)  are  the  ligaments  of  the  elbow  joint 


THE  SKELETON.  9 

The  bones  of  the  body  serve  several 
important  purposes.  1.  They  give  the 
body  its  general  shape.  2.  They  sup- 
port the  softer  material  of  the  body  within  and 
around  them.  3.  They  protect  delicate  and  impor- 
tant parts  against  injury  from  without,  as,  for  exam- 
ple, the  brain,  lungs  and  heart.  4.  They  serve  as 
levers,  to  be  moved  by  the  muscles  in  the  various 
movements  of  the  body,  as  we  shall  learn  more 
clearly,  somewhat  later. 

^  the  figure  of  the  skeleton 


of  the         we  perceive  that  the  bones  are  grouped 

Skeleton.        .    ,      -  ,     ,.    .    .  ,  1 

into  four  natural  divisions,  namely:  1. 
The  bones  of  the  head.  2.  Those  of  the  main  body, 
or  trunk.  3.  Those  of  the  upper  extremities,  or 
arms.  4.  Those  of  the  lower  extremities,  or  legs. 

We  have  now  learned  about  the  number,  shapes, 
material,  union,  uses  and  groups  of  the  bones  of  the 
skeleton.  We  are  now  ready  to  study  the  more 
important  bones  of  each  group  more  closely. 


10 


ELEMENTARY  PHYSIOLOGY. 


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THE  SKELETON.  11 


BONES  OF  THE  HEAD. 


There  are  twenty-two  bones  in  the  head. 
skull,    -  0£  these  are  shaped  and  united  in 


such  a  way  as  to  form  a  sort  of  round  box  which  is 
called  the  s/atZZ,  or  cranium.  This  is  one  of  the  most 
important  parts  of  the  skeleton,  since  it  contains  the 
brain,  the  most  delicate  organ  of  the  body.  The 
word  organ,  in  physiology,  means  any  single  part  of 
the  body  which  serves  a  special  purpose.  Thus,  the 
brain,  heart,  lungs  and  veins  are  organs.  The  skull, 
or  brain-box,  is  placed,  like  a  dome,  at  the  top  of  the 
structure  of  the  body.  It  is  wonderfully  fitted  for 
the  protection  of  its  tender  contents.  It  is  shaped 
for  strength  as  well  as  for  beauty. 

The  front  of  the  skull  is  formed  by  the  frontal 
bone  (1),  or  bone  of  the  forehead.  The  two  parietal 
bones  (2)  form  the  upper  sides,  and  the  two  tem- 
poral bones  (3)  form  the  lower  sides  of  the  skull. 
At  the  back  of  the  head  (4,  back  view  of  skeleton) 
is  the  occipital  bone.  Two  more  of  the  skull  bones 
form  its  lower  part  or  base.  These  we  will  not 
name  here  ;  but  you  will  find  them  named  in  the  full 
table  of  the  bones  which  has  been  given. 

The    remaining    fourteen    bones   of  the 

The  Face. 

head  give  shape  to  the  face.  The  two 
nasal  bones  (6)  form  the  bridge  of  the  nose,  and  the 
two  malar  bones  (4)  the  prominence  of  the  cheeks. 
The  upper  jaw  is  formed  of  the  two  upper  maxillary 
bones  (7).  The  lower  jaw  bone  (8)  is  called  the 


12  ELEMENTARY  PHYSIOLOGY. 

lower  maxillary.     The  teeth  are  set  in  sockets  of 
these  maxillary  bones. 

BONES   OF  THE   TRUNK. 

The  main  body  is  called  the  trunk.  The  upper 
part  of  the  trunk  is  fitted  to  contain  the  lungs  and  the 
heart.  Its  lower  part  contains  .the  stomach,  liver  and 
bowels. 

The  great  pillar  of  the  body  is  the  spinal 
column!**  column.  It  bears  aloft  the  head — the 

crowning  part  of  the  whole  structure.  It 
supports  the  great  vital  organs  of  the  main  body. 
It  is  most  wonderfully  constructed  with  reference  to 
comfort  and  safety  of  life.  Instead  of  being  com- 
posed of  but  one  or  a  few  bones,  it  is  built  up  of 
twenty-six  pieces,  which,  while  laid  up  one  above  the 
other,  are  separated  from  each  other  by  very  elastic 
cushions  of  cartilage.  This  does  not  only  make  the 
back-bone  capable  of  bending  forward,  backward  and 
sideways,  but  it  makes  the  whole  pillar  springy,  so 
that  the  delicate  brain  which  rides  at  its  summit  is 
not  affected  by  jarring  from  the  heavy  movements  of 
the  body. 

Twenty-four  of  the  bones  of  the  spinal 

column,  or  back,  are  called  veriebrce 
These  are  firmly  bound  together  by  ligaments  and 
interlocked  with  each  other  by  their  own  projecting 
parts.  An  opening  runs  through  each  vertebra. 
These  openings  form  the  spinal  canal  through  which 


THE  SKELETON.  13 

the  spinal  cord,  of  which  we  shall  learn  hereafter, 
passes.  The  vertebrae  are  divided  into  three  sets.  The 
seven  upper  ones  are  in  the  neck.  The  next  twelve 
are  in  the  back  proper;  to  these  the  twelve  pairs  of 
ribs  are  attached.  The  five  lower  vertebrae  are  in 
the  region  of  the  loins.  They  are  very  stout,  as  the 
figure  shows,  just  as  we  would  expect  them  to  be, 
since  they  support  a  large  part  of  the  weight  of  the 
body. 

The  upper  part  of  the  trunk,  which  con- 

The  Chest. 

tains  the  heart  and  lungs,  is  called  the 
chest.  The  skeleton  of  the  chest  is  formed  behind, 
as  you  see,  by  the  middle  division  of  the  spinal  col- 
umn; on  the  sides  by  the  ribs  (12,  13),  and  in  front 
by  the  sternum  (10)  or  breast-bone.  Here,  again,  we 
find  a  wise  provision  for  the  protection  of  life.  The 
breast-bone  is  not  near  so  hard  as  most  of  the  other 
bones.  It  is  consequently  more  flexible.  The  ribs 
are  not  directly  united  to  the  sternum,  but  are  joined 
to  it  by  cartilages.  By  these  means,  a  heavy  blow 
on  the  breast,  which  otherwise  would  seriously  injure 
the  organs  within,  is  made  comparatively  harmless. 
The  plate  of  the  skeleton  shows  that  the  ribs  are 
not  all  joined  to  the  breast-bone  in  front.  Seven 
pairs  (12-13)  are  so  joined.  These  are  called  true 
ribs.  The  remaining  five  pairs  (14-15)  are  called 
false  ribs. 

The  bones  of  the  lower  part  of  the  trunk 

The  Pelvis.  ,          .,     .    .       .. 

are  shaped  and  joined  so  as  to  form  a 
large  bowl-shaped  cavity.     This  is  called  the  pelvis. 


14  ELEMENTARY  PHYSIOLOGY. 

Notice  how  broad  and  peculiarly  formed  these  two 
(3)  bones  are.  The  sacrum  (1)  bone  is  wedged 
between  these  two  bones  at  the  back. 

BONES   OF   THE  UPPER   EXTREMITIES. 

The  In  examining  the  shoulder,  we  first  notice 

shoulder,  these  two  collar-bones  (8).  Their  use  is 
to  brace  the  shoulders  properly  apart ;  so  one  end 
rests  against  the  breast-bone  and  the  other  against 
the  shoulder.  Next  comes  the  shoulder-blade.  (16). 
These  are  so  broad  to  allow  the  attachment  of  some 
very  strong  muscles  of  the  upper  part  of  the  body. 
The  upper  arm  has  one  large  bone  called 

Tin*  Vrm 

the  humerus  ( 1 ) .  The  radius  ( 2 )  and  the 
ulna  (3)  are  the  bones  of  the  lower  arm.  There 
are  eight  roundish  little  bones  in  each  wrist  (4),  five 
longer  ones  in  the  middle  of  each  hand  (5),  three 
short  bones  in  each  finger  (6,  9,  10)  and  two  in  each 
thumb  (7,  8). 

BONES   OF  THE  LOWER  EXTREMITIES. 

Here  we  meet  the  largest  bone   of  the 

The  Thigh.       _     .    ,          ,..          Tl     .  ,,     ..     .  ,, 

skeleton  (1).  It  is  called  the  femur. 
Observe  the  round  shape  of  its  upper  end  (a).  This 
is  called  the  head  of  the  femur.  Moving  in  a  hollow 
place  of  this  large  bone  (3)  ,it  forms  the  ball  and  socket 
joint  of  the  hip.  Do  not  fail  to  notice  how  securely 
the  lower  limbs  are  bound  to  the  main  body  by  these 
numerous  strong  ligaments. 


THE  SKELETON.'  15 

The  lower  leg  has  two  bones — the  tibia 
and  Foot!*  (a)>  and  the^ftwZa  (b).  The  knee-joint, 
between  the  thigh  bone  and  the  bones  of 
the  lower  leg,  is  protected  by  a  flat  bone  called  the 
knee-pan  (2).  There  are  seven  bones  in  each  heel, 
five  in  the  middle  part  of  each  foot,  three  in  each  of 
the  larger  toes,  and  two  in  each  great  toe. 

Notice  this  peculiarity  in  the  form  of  the  foot.  It 
is  curved  or  arched  from  the  heel  to  the  front. 
Here  is  another  arrangement  for  springiness,  with- 
out which,  walking  would  not  only  become  clumsy 
but  painful. 

The  bones  of  a  grown  person  are  so  much 
hardened  by  the  mineral  matter  which 
has  increased  in  their  structure,  that  they 
are  not  easily  changed  in  shape.  They  are  more 
easily  broken  than  bent.  Neither  is  the  full-grown 
joint  likely  to  change  in  shape  and  character  during 
the  active  years  of  life.  So  the  general  carriage  of 
the  body  in  adult  life,  depends  on  the  habits  and 
circumstances  which  shaped  it  in  youth.  We  have 
learned  that  in  childhood  the  bones  are  quite  flexible 
and  disposed  to  bend,  instead  of  breaking,  under  a 
strain.  For  this  reason,  children  who  begin  to  walk 
very  early  become  more  or  less  bow-legged.  Pupils 
who  are  in  the  habit  of  leaning  forward  on  the  desk, 
in  school,  will  certainly,  more  or  less  deform  their 
bodies.  If  a  boy,  in  walking,  carries  his  body  in  a 
lazy,  stoop-shouldered  position,  he  will  go  bent  and 
deformed  through  life.  Avoid  leaning  the  body 


16  ELEMENTARY  PHYSIOLOGY. 

forward  in  sitting.  When  lying  down,  do  not 
bolster  up  the  head  with  high  pillows.  While  stand- 
ing or  walking,  hold  the  head  erect,  throw  the  shoul- 
ders back,  and  take  in  full  breaths  of  air.  If  these 
positions  in  lying,  sitting,  standing  or  walking  are 
carefully  kept  in  youth,  all  the  curvings  and  efforts 
of  the  body  and  limbs  which  come  from  ordinary 
labor,  will  not  injure  them,  and  the  full-grown  figure 
will  be  straight,  graceful  and  strong. 

OUTLINE. 

THE  BONES  OF   THE  SKELETON. 

framework  of  the  body. 

208.    Eighty-seven  pairs.    Thirty-four  single. 

Shapes:    Long,  flat,  round,  irregular. 

Composed  of  animal  and  mineral  matter. 

United  by  joints,  sutures  and  cartilages. 

Bound  together  by  ligaments. 

Arranged  in  four  groups: 

Head,  Trunk,  Upper  and  Lower  Extremities. 

(*  Twenty-two  in  the  head. 
I  Fifty-four  in  the  trunk. 

WHERE?  «{  Sixty-four  in  the  upper  extremities. 
I  Sixty  in  the  lower  extremities. 
^  Eight  in  the  ears. 

(  To  give  shape  to  the  body. 

To  support  the  softer  parts  of  the  body  within  and 
WHY?  <          around  them. 

To  protect  important  organs. 
I  To  serve  as  levers  to  be  moved  by  the  muscles. 


WHAT?  4 


THE  SKELETON.  17 

SUGGESTIONS  TO  THE  TEACHER. 

Be  sure  that  the  acid  and  burning  experiments  on  the  com- 
position of  bones  are  performed  either  by  yourself  or  by  the 
pupils.  Get  a  piece  of  flat  bone  sawed  to  show  the  layers. 
Get  a  leg  joint  at  the  butcher's;  remove  muscles  and  tendons,  to 
show  the  ligaments;  then  sever  the  bones  at  the  joint  to  show 
cartilage.  Show  a  fresh  piece  of  long  bone  containing  marrow. 

TEST  QUESTIONS. 

Of  what  is  the  skeleton  composed? 
To  what  parts  of  a  house  are  the  bones  compared? 
How  many  bones  in  the  skeleton? 
Do  the  teeth  belong  to  the  skeleton  proper? 
How  many  single  bones  in  the  body? 
How  many  are  in  pairs? 
What  variety  of  shapes  have  the  bones? 
What  two  kinds  of  material  in  the  bones? 
Which  material  makes  the  bone  flexible? 
What  is  the  effect  of  the  mineral  matter? 
How  do  these  materials  vary  at  different  ages? 
What  wise  provision  in  this  arrangement? 
Why  are  the  ends  of  the  long  bones  more  spongy? 
Why  are  they  covered  with  cartilage? 
In  what  ways  are  the  bones  united? 
Locate  a  hinge-joint  of  the  body. 
Where  is  a  ball  and  socket  joint  found? 
What  bones  are  united  by  sutures? 
What  bones  are  united  by  cartilages? 
Ho\v  are  the  bones  bound  to  each  other? 
Name  four  uses  of  the  bones. 
Into  how  many  groups  are  the  bones  divided? 
What  is  the  skull? 

Point  out  on  the  Aid,  the  frontal  bone, — the  parietal — tem- 
poral— occipital. 

How  many  bones  form  the  face? 
What  two  form  the  bridge  of  the  nose? 
Where  are  the  malar  bones? 


18  ELEMENTARY  PHYSIOLOGY. 

The  upper  maxillary?    Lower  maxillary? 

What  is  meant  by  the  trunk? 

Where  is  the  spinal  column? 

Why  is  it  built  so  strong? 

How  is  it  made,  elastic  or  springy? 

What  benefit  in  this  arrangement? 

How  many  vertebrae  in  the  back-bone? 

How  many  of  these  are  in  the  neck? 

How  many  have  ribs  attached  to  them? 

How  many  are  in  the  loins? 

What  bones  make  the  frame  of  the  chest? 

Are  the  ribs  united  directly  to  the  sternum? 

Is  the  sternum  as  hard  as  other  bones? 

What  benefit  in  these  arrangements? 

How  is  the  lower  part  of  the  skeleton  of  the  trunk  shaped? 

What  is  it  called? 

What  three  bones  come  together  at  the  shoulder? 

What  two  in  the  forearm? 

How  many  in  the  wrist? 

How  many  in  the  middle  of  the  hand? 

In  each  finger? 

In  each  thumb? 

Which  is  the  longest  bone  in  the  skeleton? 

What  two  bones  in  the  lower  leg? 

How  many  heel  bones  in  each  foot? 

Why  is  the  foot  arched  instead  of  flat? 


THE  MUSCULAR  SYSTEM. 


MUSCLES. 

We  have  studied  the  framework  or  skeleton  of  the 
body.  We  have  seen  from  the  figure  of  it  in  the 
Anatomical  Aid,  how  it  resembles  the  framework  of 
a  house  before  it  is  weather-boarded  and  shingled. 
The  plate  of  the  body  which  is  now  before  us  pre- 
sents altogether  a  different  view  from  that  which  we 
have  been  studying.  We  notice  that  it  looks  more 
like  the  full  body,  more  like  a  house  that  is  enclosed. 
The  bones  are  here  quite  concealed  by  another 
division  of  organs — the  muscular  system.  The 
word  system  in  Physiology  means  the  whole  collec- 
tion of  parts  or  organs  of  the  body,  which  perform 
similar  work  or  which  work  together  for  some  com- 
mon purpose.  We  are  already  acquainted  with  the 
bony  system.  We  will  now  study  the  muscular 
system. 

The  muscles  form  the   lean  flesh  of  the 
body.     The  meat  which  we  eat  for  food 

31  uscles.  * 

is  chiefly  muscle.     We    are   all    familiar 
with    the    dark  red    color    of     beef    when     it     is 

(19) 


20  ELEMENTARY  PHYSIOLOGY. 

raw.  You  have  also  undoubtedly  noticed  that  the 
muscle  or  lean  meat  of  pork  is  of  a  paler  red,  and 
the  meat  on  the  breast-bone  of  a  chicken  is  quite 
white;  so  muscle  is  not  always  red;  but  it  is  gen- 
erally red,  and  the  plate  shows  us  that  the  muscles 
of  the  human  body  are  of  a  quite  red  color. 

There  are  527  muscles  in  your  body. 
Number   and     Each  one  of  these  is  made  up  of  many 

Structure    of  J 

Muscles.  strands  or  string-like   fibers.     These 

are  laid  side  by  sjde  in  the  mniscle, 
sometimes  making  quite  a  thick  bundle.  Each  fiber 
of  a  muscle  bundle  is,  however,  separated  from  the 
rest  by  a  very  delicate  substance.  If  you  will  take 
a  piece  of  cooked  meat,  when  it  is  cold,  yo^  can  pull 
the  muscles  apart  into  strands,  and  these  strands 
can  be  separated  into  many  finer  fibers  or  threads  of 
muscle.  "While  this  is  being  done,  you  can  observe 
the  breaking  and  crackling  of  the  very  thin  layer  of 
matter  which  separates  the  fibers.  The  muscles 
differ  from  each  other  in  shape.  Some  are  spread 
out  much  like  a  fan.  Others  are -quite  circular  in 
form,  like  this  one  (5)  around  the  eye,  or  this  (15) 
around  the  mouth.  Some  are  quite  long  and  of 
nearly  even  thickness.  The  largest  muscle  in  the 
body  is  this  (60),  called  the  tailor  muscle.  It  is 
nearly  a  yard  long  and  does  the  work  of  crossing 
the  legs. 

The  ends  of  the  muscles  are  attached  to 
the  bones  by  means  of  a  hard  white  sub- 
stance or  cord,  which   is   called  a  tendon.     These 


THE  MUSCULAR  SYSTEM.  21 

tendons  are  very  strong.  Besides  binding  the 
muscles  very  fiiiniy  at  their  ends  to  the  bones,  they 
are  very  usefal  :n  giving  a  graceful  shape  to  many 
parts  of  the  body.  For  instance,  if  these  (39  and 
40)  muscles  of  the  forearm,  which  must  have  a  con- 
nection with  the  fingers,  were  all  continued  as  mus- 
cular bundles,  through  the  wrist,  hand  and  finger- 
joints,  the  hand  would  have  a  very  clumsy  figure. 
But  these  muscles  reach  out  to  the  finger- joints  by 
means  of  their  tendons,  and  these  tendons  are 
neatly  bound  down,  to  run  snugly  along  the  bones, 
by  means  of  ligaments,  Kke  this  (45),  so  that  the 
hand  is  really  a  very  shapely  organ.  This  (63)  shows 
the  tendon  of  this  (62)  muscle  of  the  leg,  and  here 
(68)  is  the  tendon  of  this  (66)  large  muscle  of  the 
thigh. 

The  muscles  have  been  very  appropriately 
the  called  "our  servants,"  furnished  us  with 

Muscles.        u  the  -house  ^  which  we  liye  »       They  are 

indeed  very  faithful  servants.  It  is  their  work  to 
move,  in  many  ways,  the  different  parts  of  the  body ; 
or,  as  in  walking,  to  move  the  body  as  a  whole. 
There  is  no  movement  of  any  part  of  the  body  which 
is  not  produced  by  the  action  of  one  or  more  mus- 
cles. Every  step  we  take,  the  slightest  motion  of  a 
finger,  the  movement  of  the  lips  in  speaking,  the 
chest  in  breathing,  or  the  eye  in  winking  - —  all 
these  movements  are  produced  by  the  muscles. 
The  rapidity  with  which  these  muscles  work 
is  quite  astonishing.  To  be  convinced  of  this, 


22  ELEMENTARY  PHYSIOLOGY. 

we  may  observe  the  movements  of  the  fingers 
of  a  skillful  pianist  or  a  rapid  type-writer.  To  help 
you  understand  still  better  how  very  rapidly  the 
muscles  can  act,  you  may  remember  that  in  say- 
ing the  one  word  muscle,  the  mouth,  tongue  and 
voice  organs  must  be  pat,  in  succession,  into  four 
different  shapes  or  positions,  all  of  which  is  done  by 
the  proper  muscles.  We  must  not  get  the  idea  that 
only  the  bones  are  moved  by  the  muscles.  Many 
other  parts  of  the  body  are  moved  by  their  action. 
For  instance,  the  lips  in  whistling,  the  eye -lids  in 
winking,  the  skin  in  wrinkling  the  forehead,  or  the 
heart  in  its  ceaseless  beating.  When  a  dog  pricks 
up  his  ears,  or  a  horse  drives  off  the  flies  by  shak- 
ing his  skin,  it  is  done  by  the  action  of  the  muscles. 
There  is  another  use  which  the  muscles 

Language 

of  the  serve,  which  is  very  interesting.     It  may 

be  called  the  language  of  the  muscles, 
and  it  is  remarkable  how  often  they  speak  for  us. 
A  frown  on  the  face  is  purely  the  work  of  the  mus- 
cles; yet  everybody  understands  its  meaning.  The 
same  is  true  of  a  smile.  You  see  two  men  at  a  dis- 
tance standing  face  to  face  and  near  together,  with 
clenched  fist  and  up-raised  arm.  You  do  not  hear  a 
word  they  say,  but  the  action  of  their  muscles,  which 
you  see,  tells  you  how  they  feel.  You  pass  near  by 
a  vicious  horse,  as  he  lays  back  his  ears,  or  approach 
a  dog  whose  hair  on  his  neck  is  drawn  up  stiff  and 
straight,  you  hear  no  sounds,  but  you  understand 
the  warning.  It  is  the  silent  but  expressive  lan- 
guage of  the  muscles. 


THE  MUSCULAR  SYSTEM.  23 

_      v  Some  of  the   muscles  of  the  body  act 

Two  Kinds  » 

of  Muscular  only  when  they  are  directed  to  do  so  by 
the  mind  or  the  will,  These  are  called 
voluntary  muscles.  Others  act  without  being  con- 
trolled by  the  will.  These  are  called  involuntary 
muscles.  The  muscles  of  the  arm,  for  example,  are 
voluntary  muscles.  The  muscles  which  produce  the 
action  of  the  heart  are  involuntary.  Some  muscles 
may  act  either  with  or  without  the  action  of  our  will. 
For  instance,  the  muscles  which  produce  winking 
usually  "  wait  for  no  thinking."  But  we  may  will  to 
wink,  and  wink  whenever  we  please.  On  the  other 
hand,  the  will  usually  controls  the  action  of  the 
motion  of  the  jaws.  But  sometimes,  as  in  the  case 
of  a  chill,  these  muscles  produce  chattering  of  the 
teeth  rather  contrary  to  the  direction  of  the  will. 
HOW  the  Motion  is  produced  by  the  muscles,  by 
the  contraction  of  the  fibers.  A  muscle 


Act. 

shortens  more  or  less  according  to  the 
degree  of  motion  which  it  is  to  produce.  The  short- 
ening in  length  is  caused  by  a  swelling  out  of  the 
muscles  sideways.  This  swelling  or  bulging  of  a 
muscle  can  easily  be  perceived  while  it  is  contracted 
and  pulling  or  holding  the  part  which  it  moves. 
Grasp  your  arm  between  the  elbow  and  shoulder 
firmly  between  your  thumb  and  fingers.  Now  raise 
your  forearm  toward  your  shoulder;  you  feel  the 
thickening  of  the  muscle  which  raises  your  arm. 
This  (84)  is  the  muscle  whose  action  you  so  plainly 
feel.  It  is  called  the  biceps  muscle  of  the  arm.  This 


24  ELEMENTARY  PHYSIOLOGY. 

name  means  double-beaded,  and  this  muscle  is  so 
called  because  it  lias  two  upper  tendons  or  starting 
places.  Here  (32)  is  the  one,  and  here  (33)  is  the 
other.  The  return  of  the  muscle  to  its  usual  shape 
and  length  is  called  its  relaxation.  The  relaxation 
of  this  (34)  biceps  must  take  place  to  permit  the 
arm  to  straighten  out;  but,  at  the  same  time,  some 
other  muscle  or  muscles  must  contract  to  move  it 
into  the  straight  position.  A  muscle  which  bends  a 
part  is  called  a  flexor.  One  which  serves  to 
straighten  a  part  is  called  an  extensor. 
.  .  ._  Most  of  the  muscles  of  the  body  are 

Antagonists,  J 

or  counter  paired  off  in  their  work.  That  is,  the 
motion  of  a  part  produced  by  a  certain 
muscle  is  reversed  by  the  contraction  of  some  other 
muscle.  Such  muscles  are  called  antagonists,  or 
counter  muscles.  Here  again  we  refer  to  the  chart 
for  illustration.  To  raise  the  forearm,  as  we  have 
seen,  this  (34)  biceps  must  contract  ;  but  to  straighten 
it  out  again  requires  the  action  of  this  muscle  (36), 
the  triceps.  So  the  biceps  and  triceps  are  antag- 
onists. These  muscles  (43  and  44)  bend  the  fingers, 
while  these  (51  and  52)  straighten  or  extend  them  — 
another  illustration  of  counter  muscles. 

The  names  of  the  muscles  are  very 


Prominent  . 

and  long  and  difficult  to  remember.     It 

Their  Names.  wouu  be  unwise  and  unreasonable 
•to  ask  you  now  to  learn  many  of  them.  But  by 
studying  a  few  of  the  more  prominent  ones  you  will 
learn  something  about  their  uses,  and  also  how  their 


THE  MUSCULAR  SYSTEM.  25 

names  are  formed.  This  (1)  muscle,  which  occu- 
pies a  very  prominent  place,  begins  on  the  occipital 
or  back  bone  of  the  head,  and  reaches  forward  to  the 
skin  of  the  forehead  over  the  frontal  bone.  Its  con- 
traction raises  the  eyebrows  and  wrinkles  the  forehead. 
It  is  called  the  occipito-frontalis.  It  takes  its  name 
from  the  parts  which  it  connects.  This  (15)  curious 
muscle,  when  it  contracts,  puckers  the  lips.  Physi- 
ologists call  it  orbicularis  oris.  Orbicularis  means 
circular,  and  oris  means  of  the  mouth.  So  this 
muscle  is  named  from  its  shape  and  position.  Here 
(51)  is  a  muscle  which  bears  the  name  extensor 
indicis,  which  means  the  straightener  of  the  index 
finger,  this  being  precisely  the  work  which  the 
muscle  performs.  This  muscle  (22)  takes  its  name 
from  its  position  under  the  clavicle  or  collar-bone. 
So  it  is  called  the  sub-clavian  muscle.  We  see  that 
some  muscles  are  named  after  the  parts  which  they 
connect;  some  from  their  shape  and  position;  some 
from  the  work  which  they  do,  and  others  from  their 
location.  So  the  many  long  and  difficult  names  of 
the  muscles  which  you  find  on  this  plate  (to  which 
the  figure  seems  to  be  pointing),  and  which  are  so 
meaningless  to  you  now,  are  really  very  expressive 
and  full  of  meaning,  and  may,  some  day,  when  you 
are  more  advanced  in  your  studies,  become  very 
interesting  to  you. 

Health         ^ie    com^or*  °^  the  body,  its  grace    of 

of  the          form  and  the  prompt  activity  of  all  its 

es'     parts  depend  very  largely  on  the  healthy 


26  ELEMENTARY  PHYSIOLOGY. 

and  vigorous  condition  of  all  the  muscles.  To  keep 
them  all  in  that  condition,  each  one  mast  be  used 
without  being  abused.  A  muscle  which  is  not  used 
loses  its  power  of  contraction,  becomes  weak  and 
flabby,  and  finally  altogether  useless.  On  the  other 
hand,  if  a  muscle  is  overworked,  it  loses  its  power. 
If  you  were  to  tie  up  your  arm  in  a  sling,  or  bind  it 
down  to  your  side  for  a  long  time,  you  would  lose 
the  use  of  it  entirely.  If  you  should  swing  your  arm 
for  a  long  time,  the  muscles  which  produce  its  motion 
would  cry  out  in  paiuful  protest  against  the  abuse 
which  they  suffer ;  and  were  you  to  disregard  their 
protest,  they  would  "  strike "  and  refuse,  positively, 
to  do  the  bidding  of  your  will.  The  effect  of  the 
vigorous  exercise  of  the  muscles  without  overtaxing 
them,  is  to  make  them  firm  and  strong;  the  stout 
arm  of  a  blacksmith,  and  the  strong  limbs  of  a  foot- 
man illustrate  this.  The  difference  between  the 
robust  figure  and  good  health  of  a  sturdy  country 
boy  and  the  slender  body  and  feeble  strength  of  his 
young  friend  in  the  city,  lies  mostly  in  the  difference 
in  amount  of  their  general  muscular  exercise.  But 
we  must  be  careful  not  to  mistake  a  bulky  body,  or 
thickness  of  the  limbs,  as  a  sign  of  stoutness  and 
strength  of  muscle.  It  is  true,  indeed,  that  as  the 
muscles  grow  stronger  they  grow  thicker,  and  conse- 
quently increase  the  size  of  the  limbs  and  trunk  of 
the  body.  But  the  effect  of  the  fat  of  the  body  is 
often  mistaken  for  an  "  abundance  of  muscle." 


THE  MUSCULAR  SYSTEM. 


27 


OUTLINE. 
THE   MUSCLES. 

f  The  lean  flesh  of  the  body. 
Color,  red.    Number,  527. 
Composed  of  many  fibers. 
Shapes  :  long,  fan-shaped,  flat  and  circular. 
Bound  to  the  bones  by  tendons. 
WHAT?  ^  Voluntary  and  involuntary. 
Have  power  of  contraction. 
Swell  out  when  they  shorten. 
Antagonists  produce  counter  motion. 
Flexors  bend,  extensors  straighten. 
I  Are  kept  healthy  by  exercise. 

WHERE?  -^  Found  distributed  in  all  parts  of  the  body. 


WHY? 


To  give  motion  to  all  parts  of  the  body  by  the 
contraction  and  relaxation  of  their  fibers. 

SUGGESTIONS   TO   THE    TEACHER. 


In  these  lessons,  whether  you  teach  them  by  oral  exercises 
or  in  recitation  by  the  pupils,  you  can  add  much  interest  and 
practical  instruction  by  bringing  before  your  class  illustrations 
of  the  real  working  of  the  parts  or  organs  which  are  being 
studied.  This  can  often  be  done  very  conveniently,  and  will 
contribute  much  to  the  pupils'  knowledge  of  the  functions  or 
use  of  the  organs  (physiology),  while  the  Anatomical  Aid  gives 
them  a  correct  view  of  the  structure  (anatomy)  of  the  parts.  In 
studying  the  muscles,  especially,  such  real  examples  of  their 
work  are  very  easily  given.  Name  and  point  out  on  the  plate 
a  certain  muscle.  Make  it  serve  your  will  as  your  pupils  look 
on.  Then  let  the  class,  in  concert,  join  you  in  the  perform- 
ance. Wrinkle  the  forehead,  close  the  eyes,  pucker  the  mouth, 
swell  the  cheeks,  raise  the  arm,  etc.  This  will  make  the 
information  which  is  imparted  "stick,"  because  it  is  stored 
in  the  mind  among  the  pleasures  of  memory. 

The  "drum-stick"  of  a  chicken — which  some  pupil  may 
like  to  contribute — will,  at  this  stage,  furnish  a  very  good  object- 


28  ELEMENTARY  PHYSIOLOGY. 

lesson.  Show  how  the  muscles  are  grouped  about  the  upper 
part  and  gradually  taper  down  to  the  bone.  Below  the  muscle, 
lying  along  the  bone,  is  a  tendon.  Separate  the  muscle.  If 
the  "drum-stick"  has  become  cold,  after  having  been  cooked, 
you  may  hear  the  crackling  of  the  delicate  little  sheaths  which 
encase  the  fibers.  When  you  have  removed  all  the  muscles, 
you  have  left  two  representatives  of  the  bony  system — the 
larger  bone,  the  tibia,  and  the  slender  bone  by  its  side,  the 
fibula,  corresponding,  in  position,  to  the  same  bones  in  the 
human  body. 

TEST   QUESTIONS. 

What  part  of  the  body  do  the  muscles  form? 

What  is  the  usual  color  of  the  muscles? 

How  many  muscles  are  in  the  body? 

What  can  you  tell  of  the  structure  of  a  muscle? 

How  do  muscles  differ  in  shape? 

What  is  the  shape  of  the  muscle  which  closes  the  eye? 

What  and  where  is  the  longest  muscle  of  the  body? 

What  is  the  use  of  the  tendons? 

Can  you  explain  how  the  tendons  assist  in  giving  a  graceful 

shape  to  the  body? 
What  is  the  use  of  the  muscles? 

What  parts,  besides  the  bones,  are  moved  by  the  muscles? 
Can  you  give  an  illustration  of  the  language  of  the  muscles? 
What  is  meant  by  a  voluntary  muscle? 
What  is  an  involuntary  muscle? 
What  is  meant  by  the  contraction  of  a  muscle? 
What  by  relaxation? 

What  is  the  difference  between  a  flexor  and  extensor  muscle? 
What  are  antagonists  or  counter  muscles? 
How  is  a  muscle  affected  by  being  unused? 
What  is  the  result  of  too  severe  exercise? 
Is  a  bulky  body  always  a  strong  body? 
What  is  likely  to  make  the  body  bulky? 


THE   NERVOUS    SYSTEM. 


So  far  as  we  have  now  studied  the  body  we  have  its 
framework  and  the  muscles  which  are  to  give  motion 
to  its  various  parts.  We  have  learned  how  the  mus- 
cles act,  and  now  comes  the  question :  "What  causes 
them  to  act  as  they  do?  We  have  learned  of  the 
obedience  of  the  voluntary  muscles  to  the  will.  But 
how  does  the  mind  or  will  direct  them  token,  how 
much,  and  how  long  to_act?  For  the  purpose  of 
enabling  the  mind  to  control  the  action  of  .the  mus- 
cles, a  very  interesting  system  of  organs  is  provided 
in  the  body,  namely,  the  nervous  system.  This  plate 
gives  us  an  excellent  view  of  it. 

The  brain  is,  in  many  respects,  the  most 

The  Brain.        .  _  ,.       _  r  1 

important  organ  of  the  body.  It  occu- 
pies the  loftiest  chamber  of  the  body  house.  (Raise 
the  face  section  and  refer  to  the  brain  on  plate. ) 
Here  the  mind — the  invisible  tenant  or  occupant  of 
the  body — seems  to  form  its  purposes  and  send  out 
its  orders  to  its  hundreds  of  servants  stationed  at  as 
many  points,  between  top  and  toe.  Here,  also,  it 
receives  its  messages  of  intelligence  from  the  body 

and  from  the  outside  world.     These  messages  may 

(29) 


30  ELEMENTARY  PHYSIOLOGY. 

bring  it  pleasure  or  pain ;  and  they  largely  influence 
its  decisions,  its  orders  and  its  temper. 

The  brain  is  an  exceedingly  soft  and 

Structure.  .  &  J 

delicate  organ.  If  it  were  not  enclosed 
in  a  triple  sac  and  nicely  fitted  into  its  bony  cham- 
ber it  would  fall  apart  from  its  own  weight.  It  is 
composed  of  two  kinds  of  substance,  one  of  which  is 
gray  in  color  and  the  other  white.  The  outer  por- 
tion of  the  brain  is  composed  of  the  gray  matter. 
The  white  matter  occupies  the  inside  portion. 

The  brain  is  surrounded  by  three  coats 
Protection  or  membranes.  The  one  lying  next  to 

to  the  Brain.  J      & 

it  is  a  delicate  covering  containing 
vessels  which  supply  the  brain  with  blood.  This 
membrane  takes  its  name  from  its  purpose  of  careful 
protection ;  so  it  is  called  the  pia  mater  —  which 
means  a  tender  mother.  It  lies  very  close  to  the 
surface,  stretching  over  the  little  hills  and  dipping 
down  into  the  little  valleys,  with  which  the  outside 
of  the  brain  is  covered.  Next  to  the  pia  mater  lies 
a  membrane  so  delicate  that  it  was  named  after  a 
spider's  web — arachnoid.  This  membrane  performs 
its  work  of  protection  by  collecting  from  the  blood  a 
watery  fluid  to  moisten  the  surface  of  the  brain  and 
prevent  any  possible  friction.  The  outer  coat  is  quite 
tough  and  substantial:  so  it  is  called  the  dura  mater, 
or  hard  mother.  It  lies  close  to  the  inside  surface 
of  the  skull  bones.  Now  wo  can  see  how  the  brain 
is  protected,  for  instance,  against  a  blow  on  the  head. 
The  effectof  such  a  blow  would  be  diminished,  first,  by 


THE  NERVOUS  SYSTEM.  31 

the  hair,  then  by  the  skin  and  muscles  overlying  the 
skull,  then  by  the  bone,  next  by  the  hard  coat,  then 
by  the  water  coat,  and  finally  by  the  soft  coat — mak- 
ing no  less  than  a  half-dozen  successive  defenses 
against  harm  to  the  castle  of  the  mind. 

The  brain  is  divided  into  two  parts,  one 

°^  whicl1  is  mucb  larger  tnan  the  other. 

These  parts  are  shown  here,  in  this 
section  which  represents  the  head  as  divided  from 
top  to  bottom,  close  behind  the  ears.  We  will  now 
refer  to  the  manikin  of  the  head,  where  we  will  get 
a  very  clear  view  of  the  size  and  position  of  these 
brain  parts.  (Fourth  section  of  the  head.)  This 
(74)  large  upper  brain  is  called  the  cerebrum.  It 
fills  the  whole  front  and  upper  part  of  the  brain-box. 
The  small  brain  (75)  is  called  the  cerebellum. 
Notice  that  it  lies  behind  and  below  the  large  divi- 
sion of  the  brain.  When  this  small  brain  is  cut 
through,  its  inner  structure  has  this  tree-like  appear- 
ance (shown  on  plate),  called  the  arbor  vitce. 

Both    the    cerebrum    and  cerebellum 

Hemisphere*.  «••••*•,  n     i    AT 

are  divided  into  two  parts,  called  the 
right  and  left  hemispheres.  The  lower  parts  of  the 
two  hemispheres  are  united  by  several  small  mys- 
terious-looking organs,  whose  particular  use  has 
been  a  puzzle  even  to  many  wise  heads,  but  which 
certainly  have  some  special  part  to  perform  in  the 
wonderful  control  of  the-mind  over  the  body.  The 
last  section  of  the  head  (turn  to  it),  which  repre- 
sents it  as  cut  through  from  front  to  back,  in  the 


32  ELEMENTARY  PHYSIOLOGY. 

middle,  shows  us  the  right  hemisphere  of  both  the 
larger  and  the  smaller  brain.  The  red  vessels,  in  the 
figure,  are  blood-vessels  which  bring  large  quantities 
of  the  purest  blood  in  the  body  to  the  brain,  for  a 
purpose  of  which  we  shall  learn  hereafter. 

From  many  observations  and  experi- 
ments  which  have  been  made  by 
physiologists,  it  has  been  learned 
that  the  large  brain  is  the  thinking  organ  of  the 
mind.  It  is  here  that  impressions  received  from 
the  outside  world  are  translated  into  thought  and 
feeling.  Here  the  purposes  of  the  will  are  formed, 
and  from  here  all  orders  for  the  action  of  the  volun- 
tary muscles  are  issued. 

The  work  of  the  small  brain  seems  to 

Work  of  the    ,  .    .  , 

cerebellum  "e  to  regulate  the  muscuJar  movements 
which  are  directed  to  be  made  by  the 
large  brain.  It  has  been  discovered  that  when  the 
cerebellum  is  injured,  a  person  can  not  balance 
the  body,  as  is  required  even  in  standing  and  much 
more  in  walking.  A  bird  whose  small  brain  is 
seriously  injured  or  removed,  can  move  its  wings 
and  its  legs,  but  it  can  neither  fly  nor  walk. 

The  nervous  matter  of  the  brain  is  con- 
Cord.  P"  *  tinned  down  through  the  back,  passing 

through  openings  in  the  bones  of  the 
spinal  column.  This  is  called  the  spinal  cord.  Here 
(131,  last  section  of  the  head)  is  where  the  spinal 
cord  begins.  This  (124)  upper  part  of  the  cord 
(medulla  oblongata)  is  a  very  important  part  of  the 


THE  NERVOUS  SYSTEM.  33 

nervous  system,  for  the  reason  that  it  seems  to  have 
control  of  some  of  the  most  vital  operations  of  the 
body.  When  it  is  injured,  .the  breathing  muscles 
fail  to  act,  which,  of  course,  means  instant  death. 
Here  (150)  we  see  the  spinal  cord  continued  down- 
ward. Now  we  will  turn  again  to  the  nervous  plate  of 
the  Aid,  where  the  whole  of  this  great  nervous 
cord  is  shown  with  its  numerous  branches  of  nerves. 

The  nerves  are  composed  of  the  same 
TheXerves.  ji  i_  •  mi  -i 

substance  as  the  brain.  Iney  are  sil- 
very threads  which  branch  out  from  the  brain  and 
spinal  cord  and  are  distributed  to  all  parts  of  the 
body.  Twelve  pairs  pass  out  through  openings  of 
the  cranium.  These  are  called  cranial  nerves. 
Thirty-one  pairs  pass  out  from  the  spinal  cord 
through  openings  of  the  back-bone,  as  shown  on  the 
plate.  These  are  called  spinal  nerves.  The  cranial 
nerves  go  to  the  eye,  ear,  nose,  tongue  and  other 
important  organs.  The  spinal  nerves  go  to  the 
arms,  trunk  and  legs. 

Besides  the  nerves  which  branch  out  from  the 
brain  and  spinal  cord,  there  is,  on  each  side  of  the 
back-bone,  a  chain  of  nerve  centers — little  bits  of 
brains,  as  it  were — running  down  through  the  body. 
From  these  small  nerve  knots,  delicate  nerves  run  out, 
some  to  the  heart,  lungs  and  stomach,  and  others  to 
the  blood-vessels  and  to  the  cranial  and  spinal 
nerves.  So  all  the  important  organs  of  the  body  are, 
in  this  way,  connected  with  each  other  and  with  the 
brain.  This  figure  (The  Sympathetic  System)  shows, 


34  ELEMENTARY  PHYSIOLOGY. 

beautifully,  this  wonderful  nervous  connection.  The 
interesting  object  of  this  arrangement — which  is 
called  the  sympathetic  nervous  system — we  shall 
soon  learn. 

There  are  three  kinds  of  nervous  action. 
Action!**  We  will  first  consider  the  relation  between 

mind,  brain  and  nerve.  The  nervous 
system  is  very  much  like  a  telegraph  system.  The 
mind  has  been  called  the  operator,  the  brain  and 
spinal  cord  the  sending  or  receiving  offices  or 
instruments,  and  the  nerves  the  wires  or  lines 
running  to  all  parts  of  the  body.  The  comparison 
is  very  apt,  indeed.  One  set  of  nerves  runs  from 
the  brain  or  spinal  cord  to  the  muscles,  so  that  every 
muscular  fiber  is  in  direct  communication  with  head- 
quarters. Now,  wherever  a  muscle  is  to  act,  every 
fiber  of  it,  in  some  mysterious  way,  gets  a  message 
over  its  nerve  line,  from  the  nervous  capital, 
directing  it  precisely  how  much  to  contract  or  relax. 
For  example,  you  make  up  your  mind  to  close  your 
eyes.  The  order  is  sent  out  over  the  nerve  lines 
which  go  to  the  fibers  of  the  circular  muscle  which 
we  have  found  to  lie  around  the  eye,  and  promptly 
the  eyelids  close.  The  nerves  which  carry  messages 
to  the  muscles  are  called  nerves  of  motion.  Another 
set  of  nerves  are  called  nerves  of  feeling.  They 
carry  impressions  from  the  body  to  the  brain.  These 
nerves  are  distributed  so  thickly  near  the  surface  of 
the  body,  in  the  skin,  that  it  would  be  almost  impos- 
sible to  find  a  point  on  the  body  where  the  prick  of 


THE  NERVOUS  SYSTEM.  35 

a  pin  would  not  be  felt.  If  you  touch  your  body  on 
its  skin  surface  anywhere,  even  with  the  fine  point 
of  a  needle,  you  are  sure  to  disturb  one  or  more  of 
the  nerves  of  feeling.  Quicker  than  thought  they 
report  the  impression,  according  to  the  degree  of  its 
severity,  to  the  brain,  which,  if  the  situation  at  the 
surface  demands  it,  will  promptly  return  an  order, 
over  the  nerves  of  motion,  to  the  muscles  of  the 
endangered  part,  to  do  their  best  to  get  it  out  of  the 
way  of  harm.  For  instance,  a  mosquito  may  alight 
on  your  forehead  so  lightly  as  to  make  no 
impression  on  your  nerves  of  feeling,  and,  con- 
sequently, you  are  not  aware  of  it.  But  now  he 
punctures  the  skin  and  touches  a  nerve  with  his 
wonderful  little  stiletto.  The  news  of  his  attack  has 
been  received  by  the  brain,  and  an  order  sent  back 
for  defense  and  protection.  Quicker  than  thought 
your  hand  has  come  up  and  routed  or  crushed  the 
little  assassin. 

But  the  impressions  which  the  nerves  df  feeling 
carry  to  the  brain  and  mind  are  not  all  alarming  or 
painful.  Many  of  them  are  impressions  of  comfort 
or  pleasure.  A  gentle  breeze  fans  your  body  on  a 
hot  summer  day.  Hundreds  of  nerves  are  telling 
it  to  the  mind,  which  enjoys  it  as  a  pleasure.  Light 
impresses  the  nerve  of  sight,  and  beautiful  views 
of  form  and  color  are  spread  before  the  mind. 
Sound  excites  the  nerve  of  hearing  and  the  charms 
of  music  are  enjoyed.  Invisible  particles  from  a 
rose  come  in  contact  with  the  nerve  of  smell  and  we 
are  delighted  with  the  fragrance  of  the  flower. 


36  ELEMENTARY  PHYSIOLOGY. 

If  all  the  muscles  were  voluntary  muscles, 
Nervous  that  is,  if  no  movement  of  the  organs  of 
on*  the  body  could  be  made  without  a  special 
order  from  the  mind,  the  continuance  and  enjoyment 
of  life  would  be  impossible.  Every  breath,  every 
heart- beat,  and  many  other  operations  of  organs 
which  can  scarcely  be  dispensed  with  for  even  a  few 
moments,  would  need  to  be  constantly  thought  of 
and  directed.  Fortunately,  the  mind,  and  even  the 
brain,  is  relieved  from  the  ordinary  control  of  the 
operations  of  organs  upon  whose  regular  and  con- 
stant action  cur  life  depends.  So  the  heart  goes  on 
beating,  the  lungs  continue  breathing  and  the  stom- 
ach keeps  on  working,  while  the  mind  rests  and  the 
brain  sleeps.  Let  us  see  how  this  is  done. 

The  spinal  cord  may  be  regarded  as  a  continua- 
tion of  the  brain.  It  is  composed  of  the  same  two 
kinds  of  matter — white  and  gray.  We  may  also  look 
upon  the  spinal  cord  as  a  deputy  brain.  A  deputy 
is  appointed  as  a  substitute  for  another,  and  empow- 
ered to  act  for  him.  An  officer  may  have  more  duties 
to  perform  than  he  can  personally  attend  to.  So  an 
assistant  is  given  him,  who  is  entrusted  with  certain 
lines  of  work  for  which  he  is  held  responsible.  When 
serious  questions  or  difficulties  arise  in  the  assist- 
ant's department  of  work,  he  appeals  for  special 
advice  to  the  chief  officer.  So  in  the  body,  while  the 
brain  executes  the  orders  of  the  mind,  and  controls 
the  voluntary  operations  and  movements  of  the  body, 
the  spinal  cord  is  entrusted  with  the  control  of  the 


THE  NERVOUS  SYSTEM.  37 

involuntary  muscles  which  perform  the  work  of  the 
heart,  lungs,  stomach  and  other  vital  organs,  except 
in  cases  of  emergency.  For  example,  when  food 
comes  into  the  stomach,  certain  movements  of  the 
walls  of  that  organ  are  necessary.  So  the  food  makes 
an  impression  on  the  nerves  which  report  its  pres- 
ence, not  to  the  brain  or  to  the  mind,  as  a  sensation, 
but  to  the  origin  center  of  those  nerves,  in  the  spinal 
cord.  Here  the  cord  exercises  its  authority  and 
returns  (reflects)  an  order  over  motor  nerves  to  the 
muscles  of  the  stomach  to  perform  the  needed 
service. 

In  the  same  way,  the  presence  of  impure  air  or 
the  absence  of  air  in  the  lungs  causes  impressions 
which  are  carried  to  the  cord,  which  returns  orders 
for  the  action  of  the  breathing-out  or  breathing-in 
muscles,  as  the  case  may  be.  All  these  performances 
go  on  steadily,  whether  we  are  awake  or  asleep. 
But  when  an  emergency  arises,  as,  for  instance,  if 
the  muscles  of  the  chest  are  strongly  resisted  in  their 
efforts  to  expand  it,  by  outside  compression,  the 
news  of  the  trouble  is  carried  beyond  the  nerve  cen- 
ters of  the  cord  up  to  the  brain,  where  the  mind 
quickly  grasps  the  situation  and  promptly  issues 
orders  for  the  best  possible  measures  of  relief.  A 
familiar  illustration  of  reflex  action  is  found  in  the 
flapping  of  a  fowl  whose  head  has  been  cut  off.  Its 
muscles  which  produce  its  violent  motions  are  not  in 
connection  with  the  brain,  and  can  not  be  controlled 
by  it.  Each  fall  to  the  ground  produces  an  impres- 


38  ELEMENTARY  PHYSIOLOGY. 

sion  which  starts  from  the  cord  a  message  for  the 
repetition  of  these  muscular  movements.  Even 
when  it  seems  to  have  settled  down  quietly,  if  you 
touch  its  body  the  movements  will  be  renewed. 

s  m  athetic    ^e   ^ave   seen   ^ow   the    sympathetic 
nerves  connect  important  organs  with 


each  other  and  each  with  the  brain.  So 
if  one  organ  suffers,  the  others  suffer  more  or  less 
with  it.  When  the  stomach  is  distressed,  the  head 
aches.  When  the  heart's  action  is  excited,  the 
stomach  is  affected.  When  the  brain  is  impressed 
with  the  mind's  sense  of  shame  or  modesty,  the  little 
blood-vessels  in  the  skin  of  the  cheeks  swell  out  and 
are  more  than  usually  filled  with  blood,  and  we  call 
this  delicate  expression  of  their  sympathy,  blushing. 
Health  of  ^e  wou^  naturally  suppose  that  organs 
the  Nervous  so  delicately  constructed,  and  yet  so 

prominent  in  the  operations  of  the  body 
as  those  of  the  nervous  system,  would  need  the  most 
proper  care  to  prevent  their  derangement  or  injury. 
And  so  it  is.  The  brain  needs  especial  care.  It 
needs  rest  at  proper  intervals  ;  not  only  from  severe 
application,  but  the  complete  rest  of  sleep.  An 
overworked  brain  is  a  diseased  brain.  On  the  other 
hand,  the  brain  must  have  a  proper  amount  of  exer- 
cise to  keep  it  in  vigor.  Besides  healthy  and  varied 
exercise,  the  brain  needs  pure  blood  regularly  and  in 
proper  quantities.  Too  much  or  too  little  blood  will 
paralyze  it.  Hence  its  dependence  on  the  proper 
action  of  the  blood-circulating  system.  Impure 


THE  NERVOUS  SYSTEM. 


39 


blood  will  weaken  its  action.  Hence  its  dependence 
on  the  blood-purify  ing  system. 

Severe  excitement  of  the  mind  or  long  continued 
anxiety  cripple  the  work  of  the  brain,  and  finally 
result  in  insanity.  A  cheerful  state  of  the  rnind  is 
favorable  to  healthy  nerves  and  long  life.  Conse- 
quently, all  proper  enjoyments,  as  the  delights  of 
music,  pleasant  changes  of  scenery,  varied  means  of 
recreation  and  social  pleasures,  are  like  tonics  to  the 
nervous  system  first,  and  through  it  to  the  whole  body. 

There  is  no  system  of  the  body  that  is  more 
severely  outraged  by  the  habit  of  drink  and  the  use 
of  narcotics  than  the  nervous  system.  But  this  sub- 
ject is  so  very  important  that  it  will  be  fully  explained 
in  a  special  chapter,  after  we  are  still  better 
acquainted  with  the  structure  of  the  body. 

OUTLINE. 
THE   NERVOUS   SYSTEM. 

Consists  of  brain,  spinal  cord  and  nerves. 
Very  soft  and  delicate  in  structure. 
Composed  of  white  and  gray  matter. 
The  large  brain  called  the  cerebrum. 
The  smaller  brain  the  cerebellum. 
Right  and  left  halves  of  brain — called  hemispheres. 
Nerves  of  two  kinds,  nerves  of  sensation  or  im- 
pression and  nerves  of  motion. 

f  Brain  enclosed  in  cranium. 
Spinal  cord  extends  from  base  of  brain  through 

the  spinal  canal  of  back-bone. 

WHERE.  ^  Nerves  branch  out  from  the  brain,  spinal  cord  and 
the  sympathetic  nerve  knots,  and  are  distributed 
to  all  parts  of  the  body. 


WHAT? 


40  ELEMENTARY  PHYSIOLOGY. 

To   serve  the  mind  in  directing  the    voluntary 

movements  of  the  body. 
To  control,  by  reflex  action,  the  involuntary  mus- 

WHY?  •{      cles* 

To  bring  to  the  mind,  from  the  body  and  from  the 

outside  world,  impressions  producing  the  sensa- 
tions or  feeling  of  touch,  taste,  light,  sound, 
smell,  pain  or  pleasure. 

QUESTIONS. 

What  are  the  organs  of  the  nervous  system? 

What  position  in  the  body  does  the  brain  occupy? 

Whose  special  instrument  does  the  brain  seem  to  be? 

What  can  you  say  of  the  brain's  structure? 

What  difference  in  the  color  of  its  substance? 

Describe  how  the  brain  is  protected. 

What  is  the  cerebrum? 

What  is  the  cerebellum? 

What  is  the  arbor  vitse? 

What  is  meant  by  the  hemispheres  of  the  brain? 

What  can  you  tell  of  the  work  of  the  cerebrum? 

What  seems  to  be  the  use  of  the  cerebellum? 

Where  is  the  spinal  cord  ? 

What  is  its  upper  part  called? 

What  makes  this  part  so  very  important? 

What  are  the  nerves? 

From  where  do  they  start? 

Where  do  they  go? 

How  many  pairs  pass  out  from  the  skull? 

What  are  these  nerves  called? 

How  many  pairs  branch  off  from  the  spinal  cord? 

What  are  these  called? 

Where  do  the  cranial  nerves  chiefly  go? 

To  what  part  are  the  spinal  nerves  chiefly  sent? 

What  can  you  tell  of  the  sympathetic  nerves? 

To  what  have  we  compared  the  nervous  system? 

Tell  what  you  can  of  the  comparison. 

Do  all  the  nerves  perform  the  same  kind  of  work? 

Explain  what  is  meant  by  the  nerves  of  motion. 


THE  SPECIAL  SENSES.  41 

What  is  meant  by  the  nerves  of  feeling? 

Does  the  mind  attend  to  all  the  movements  of  the  body? 

If  not,  will  you  explain  your  answer? 

What  kind  of  muscles  are  controlled  by  the  nervous  system 

independently  of  the  mind? 
What  is  such  nervous  action  called? 
Can  you  give  an  example  of  reflex  action? 
What  is  sympathetic  nervous  action? 
Can  you  give  an  example  of  it? 
Why  does  the  nervous  system  need  special  care? 
What  kind  of  exercise  is  needed  by  the  brain? 
By  what  habits  are  these  organs  especially  injured? 


THE  SPECIAL  SENSES. 


All  the    sensory    nerves  except    four, 
Werves  of  „  .. 

common  sen-  are      nerves     of     common    sensation. 


They  are  distributed  everywhere 
throughout  the  body.  •  They  need  no  special  organs 
to  enable  them  to  receive  impressions.  Near  the 
surface  of  the  body  or  in  the  skin,  they  end  in  little 
folds  or  loops  called  papillce.  All  the  nerves  of  the 
sense  of  touch  are  nerves  of  common  sensation. 

There  are  four  nerves  of  special  sensa- 

Xerves  of 

Special  Sen-  tion.  These  are  the  nerves  of  sight, 
hearing,  smell  and  taste.  Each  of  these 
nerves  has  a  special  organ  without  which  no  impres- 
sion can  be  received  to  be  carried  to  the  brain. 
These  organs  are  very  delicate  and  wonderful  struc- 
tures. They  are  really  special  instruments  of  the 
nervous  system. 


42  ELEMENTARY  PHYSIOLOGY. 

THE    EYE. 
(Third  Section  of  Head  Manikin.) 

This  (46)  is  one  of  the  nerves  of  special  sensa- 
tion— the  optic  nerve,  or  nerve  of  sight.  It  connects 
with  and  terminates  in  the  eye.  This  nerve  is 
impressible  only  by  light.  Without  the  eye,  the  light 
would  not  impress  it.  The  eye  is  an  instrument  to 
gather  the  light  which  is  reflected  to  it  from  objects 
and  to  bring  it  to  bear  on  the  optic  nerve  in  such  a 
way  that  an  impression  is  made  and  carried  to  the 
brain,  where  the  mind  receives  the  impression  as  a 
picture  of  the  objects  from  which  the  light  came. 
How  all  this  is  done  is  very  mysterious.  But  the 
organs  which  are  concerned  in  the  process  can  be 
easily  examined  and  studied. 

Let  us  notice,  first,  that  the  eye  is 
the  Eyl!0n  °f  l°dged  in  a  deep  socket  of  the  bones 

of  the  head.  Besides  this  feature  of 
protection,  there  is  placed  behind  and  around  the 
eye,  quite  a  layer  of  fat,  so  that,  even  if  the  eye  is 
struck,  the  force  of  the  stroke  is  very  much  lessened 
by  this  fatty  cushion.  In  front,  it  is  guarded  by  the 
eyelids,  eyebrows  and  eyelashes.  The  eyelids  serve 
as  a  curtain.  The  eyebrows  prevent  the  perspiration 
from  running  down  from  the  forehead  upon  the  lids. 
The  eyelashes  prevent  dust  from  entering  between 
the  eyelids. 

(Manikin  of  the  Eye.) 

Turning  aside  this  outer  section  which 

ratus.APP*~      represents  the  natural  open  eye,  we  see 

a  gland  lying  in  the  outer  corner  above 


THE  SPECIAL  SENSES.  43 

the  eye.  This  is  called  the  lachrymal  or  tear  gland. 
It  secretes  from  the  blood  a  watery  fluid  which  it 
pours  out  upon  the  eyeball.  By  the  act  of  winking 
the  eyeball  is  entirely  bathed  by  this  fluid,  which 
after  it  has  flowed  over  the  eye,  collects  in  a  little 
lake  at  the  inner  angle,  from  whence  it  is  drained  by 
two  little  channels  (2)  into  the  tear  duct  (1)  which 
communicates  with  the  nose.  Shedding  tears  is 
simply  an  overflow  of  this  eye-bathing  fluid,  when 
it  is  secreted  in  unusual  quantity.  At  such  times 
the  little  channels  cannot  carry  it  away  sufficiently 
rapid;  so  it  flows  over  upon  the  cheeks.  This  unu- 
sual activity  of  the  tear  gland  may  be  produced  by 
certain  states  of  the  mind,  as  sorrow  or  great  joy; 
or  by  certain  diseased  conditions  of  the  parts  about 
the  eye,  as  an  inflammation  or  a  severe  cold. 

The  eyeball  has  three  coats.    The  outer 

The  wVhite 

Coat  of  the  coat,  or  white  of  the  eye,  is  called  the 
Eyeball.  sclerotic.  It  is  a  strong,  tough  mem- 

brane which  forms  quite  a  substantial  case  into 
which  the  cornea  is  set  in  front,  like  the  glass  or 
crystal  of  a  watch.  The  sclerotic  coat  is  not  sensi- 
tive ;  that  is,  it  has  no  nerves  of  feeling.  But  it  is 
covered,  in  front,  with  a  very  delicate  membrane 
which  contains  very  fine  blood-vessels  and  nerves. 
When  these  little  blood-vessels  become  swollen  with 
an  unusual  amount  of  blood,  the  eye  is  said  to  be 
"bloodshot;"  and  when  a  cinder  or  dust  grain 
lodges  on  the  eye  and  makes  an  impression  on  the 
delicate  nerves  of  this  fine  protecting  veil,  the  sen- 


44  ELEMENTARY  PHYSIOLOGY. 

sation  is  very  painful.  No  light  passes  through  the 
sclerotic  coat;  but  the  cornea  is  very  transparent. 

Next  to  the  tough   outside  white  coat 
The  Black       Hes  ^  choraid.     This  is  a  soft  black 

t^oat. 

membrane.     It  prevents  the  reflection 

of  strong  light  from  the  inner  surf  ace  of  the  eyeball, 
and  this  serves  an  important  part  in  making  the  sight 
sharp  and  clear.  The  front  part  of  the  choroid  coat 
is  arranged  like  a  circular  curtain.  This  is  called 
the  iris.  This  is  what  gives  the  eye  its  so-called 
color.  The  difference  between  a  black  eye  and  a 
blue  eye  is,  that  the  cells  of  the  iris  of  the  one  have 
a  black  coloring  matter  in  them,  while  the  cells  of 
the  iris  of  the  other  contain  blue  coloring  matter. 
In  the  center  of  the  iris  is  a  circular  opening  called 
the  pupil  which  you  can  see  by  looking  directly  into 
the  eye  of  another  person  who  stands  close  before  you. 
Through  this  little  circular  window,  surrounded  by 
the  curtains  of  the  iris,  the  light  must  pass  on  its 
way  to  the  back  inner  part  of  the  eyeball.  The 
amount  of  light  which  passes  through  the  pupil  is 
regulated  by  an  interesting  action  of  the  iris.  When 
the  light  is  strong,  the  little  muscles  which  are 
threaded  through  the  curtain  produce  the  effect  of 
making  the  pupil  smaller  so  as  to  pass  less  light. 
When  we  go  from  a  light  place  into  a  dark,  these 
same  muscles  bring  about  an  opposite  effect,  that  is, 
the  pupil  is  made  larger  so  as  to  admit  more  rays. 
This  adjustment  of  the  curtain  of  the  eye  is  not  in- 
stantly done.  It  requires  some  time.  This  you  can 


OF   T1 

TJNIVEB 


THE  SPECIAL  SENSES. 

easily  observe.  For,  in  going  from  the  dark  into  a 
very  light  room  you  can  not  see  well  until  the  change 
in  the  size  of  the  pupil-window  of  your  eye  has  been 
made.  So,  also,  when  going  from  a  bright  room  into 
a  dark  place,  at  first  it  seems  to  be  "  pitch  dark  ;" 
but,  by  and  by,  when  your  eye  is  adjusted  to  the 
change,  you  may  be  surprised  to  find  that  it  is  not 
so  dark  after  all. 

The  third  or  inner  coat  of  the  eye  is 
the  retina.  This  lies  only  over  the  back 
part  of  the  inner  »eyeball.  It  is  really 
the  end  of  the  optic  nerve,  or  nerve  of  sight,  spread 
out  to  receive  the  impression  of  the  light  in  the  eye. 
By  turning  to  the  last  section  of  this  eye-manikin, 
we  find  this  clearly  represented.  Here  is  a  small 
part  of  the  white  coat  of  the  back  part  of  the  eye- 
ball. It  shows  the  opening  (23)  where  the  optic 
nerve  enters  through  this  coat.  Turning  down  the 
section  which  lies  just  before  this,  we  see  the  open- 
ing (21)  for  the  nerve  through  (22)  the  choroid  coat. 
Turning  forward  another  section  we  come  to  the  retina 
(15)  into  which  the  nerve  is  expanded  and  over 
which  the  blood-vessels  (19,  20)  which  enter  the 
eyeball  with  the  nerve,  are  distributed.  The  retina 
is  an  exceedingly  delicate  nervous  screen  on  which 
the  action  of  the  different  parts  of  the  eye  makes  a 
picture  of  the  object  we  look  at.  How  this  picture 
is  carried  by  the  nerve  to  the  brain  and  there  grasped 
or  perceived  by  the  mind  we  do  not  understand. 


46  ELEMENTARY  PHYSIOLOGY. 

(Sense  of  Sight.) 

Between  the  cornea  and  the  iris,  in  the 

front  Part  of  the  eye» is  a  watery  fluid 

called  the  aqueous  humor  (18).  Back 
of  the  iris  lies  the  crystalline  lens  (23).  This  is  a 
beautiful  gem-like  little  body — as  clear  as  a  crystal. 
Back  of  the  lens,  and  between  it  and  the  retina,  the 
eyeball  is  filled  with  another  clear  jelly-like  sub- 
stance called  the  vitreous  humor  (25).  The  effect 
of  these  three  humors  which  are  contained  in  the 
eye,  and  especially  the  effect  of  the  lens,  is  to  produce 
the  image  of  things  on  the  retina,  as  has  already 
been  mentioned. 

(Third  Section  of  Eye  Manikin.) 

These  muscles,  which  are  shown  to  be  attached  to 
the  outer  sclerotic  coat,  produce  some  of  the  prin- 
cipal movements  of  the  eye — upward,  downward,  in- 
ward and  outward.  By  the  way,  we  also  mention 
that  the  action  of  the  muscles  of  the  iris  in  regulat- 
ing the  size  of  the  pupil,  is  an  interesting  example  of 
what  we  have  already  learned  to  name  reflex  nervous 
action. 

THE  EAR. 

The  nerve  of  special  sensation  which 
The  iferve  goes  from  the  brain  to  the  ear  is  called 

of  Hearing. 

the  auditory  nerve.  As  the  nerve  of 
sight  is  sensitive  only  to  light,  this  is  sensitive  only, 
to  sound.  The  ear  is  an  instrument  to  collect  sounds 
and  bring  them  to  bear  on  the  auditory  nerve  in 


THE  SPECIAL  SENSES.  47 

such  a  way  that  an  impression  is  made  and  carried 
to  the  brain  to  be  recognized  by  the  mind. 

The  ear  is  divided  into  the  outer,  middle 
Outer  Ear.  and  inner  ear.  Tne  outer  ear  has  a 

more  or  less  cartilaginous  frame.  This 
allows  motion,  and,  at  the  same  time,  keeps  it  in 
shape  and  position.  It  has  also  a  few  small  muscles. 
But  in  the  human  ear  these  are  nearly  altogether 
useless,  since  men  do  not  move  or  flop  their  ears. 
In  animals  which  move  their  ears  in  various  ways, 
these  muscles  are  quite  well  developed. 

(Sense  of  Hearing.) 

From  the  outer  ear  (1)  a  tube,  a  little 
Ear  Middle  over  an  inch  long,  called  the  auditory 

canal  (2),  leads  in  to  the  middle  ear, 
where  it  is  closed  by  a  membrane  called  the  mem- 
brana  tympani,  which  means  the  membrane  of  the 
tympanum  or  drum  (3).  The  middle  ear  is  often 
called  the  "ear-drum,"  and  the  membrane  just  men- 
tioned may  be  called  the  "drum-head,"  for  it  does, 
indeed,  act  very  much  like  the  head  of  a  drum. 
Between  this  membrane  of  the  drum  and  its  inner, 
opposite  side  or  end,  there  is  stretched  a  very  curious 
little  suspension  bridge  of  four  small  bones.  The 
first  of  these  is  attached  to  the  drum-head,  and  from 
its  shape  like  a  hammer  is  celled  the  malleus  (4). 
The  next  is  called  the  incus,  because  it  is  shaped 
like  an  anvil  (7).  The  third  is  a  very  small  pebble 
of  a  bone  called  the  orbicular  or  round  bone  (10).  It 


48  ELEMENTARY  PHYSIOLOGY. 

is  followed  by  the  stapes  or  stirrup  bone  (12),  the 
last  span  in  the  little  bridge.  This  rests  against  a 
small  window-like  membrane  which  is  stretched  over 
an  opening  in  the  inner  side  of  the  drum.  At  the 
bottom  of  the  ear-drum  or  middle  ear  is  an  opening 
into  a  tube  which  leads  from  the  ear  to  the  throat 
This  is  called  the  Eustachian  tube.  Its  object  is  to 
supply  the  ear-drum  with  air,  for  without  air  inside 
to  balance  the  pressure  of  the  air  on  the  outside 
of  the  drum-head,  the  action  of  the  latter  would  be 
very  imperfect  and  our  hearing,  in  consequence,  very 
dull.  We  frequently  experience  the  truth  of  this 
statement;  for  whenever  the  Eustachian  tube  be- 
comes clogged,  as  in  the  case  of  a  very  bad  cold, 
our  hearing  is  very  much  impaired, 

The  inner  ear  is  carefully  hidden  in  a 

Ear  InnCr  h°U°w  Place  in  tne  s°li<i  bone-  In  that 
part  of  it  which  lies  next  to  the  mid- 
dle ear,  is  a  little  hall-way,  or  vestibule,  about  as 
large  as  a  grain  of  wheat.  This  leads,  on  one  side, 
into  the  arched  or  semi-circular  hall-ways  which  are 
called  the  semi-circular  canals  (13,  14,  15).  On 
the  other  side  the  vestibule  opens  into  the  cochlea 
(16, 17),  which  is  shaped  like  a  snail  shell  or  a  tiny 
winding  stair.  Here  the  auditory  nerve,  or  nerve 
of  hearing,  takes  up  the  impression  of  a  sound  and 
transmits  it  to  the  brain. 

All  sounds  are  produced  by  the  vibra- 

Hear.  tions  of  bodies.     To  make  this  plainer, 

when  a  bell  is  struck  its  particles  are 


THE  SPECIAL  SENSES.  49 

thrown  into  a  violent  trembling.  By  these  trem- 
blings or  vibrations  of  the  material  of  the  bell  the 
air  is  thrown  into  a  wave-like  motion  all  around  it. 
When  these  trembling  air  waves  reach  the  ear,  the 
sensation  of  sound  is  produced  and  we  say  we  hear 
the  bell.  When  a  person  speaks  to  us  the  voice 
chords  in  his  throat  are  set  into  rapid  vibration. 
These  vibrations  produce  waves  of  sound  in  the  air; 
the  air  carries  these  waves  to  the  ear,  where,  passing 
in  through  the  auditory  canal  they  tremblingly  beat 
upon  the  drum-head;  this  carries  the  sounds  to  the 
bridge  of  little  bones.  Having  passed  over  these, 
it  enters  the  vestibule,  then  vibrates  into  the  semi- 
circular canals  and  rebounds  into  the  cochlea,  where, 
as  already  stated,  it  is  taken  up  by  the  nerve  and 
carried  to  the  brain  where  the  mind  interprets  it  as 
the  voice  and  the  language  of  the  speaker. 

THE  SENSE  OF  SMELL. 

The  organ  of  smell  is  the  nose  and  its  cavities. 
The  nerve  of  smell  is  called  the  olfactory  nerve. 
This  nerve  is  spread  out  in  many  branches  over  the 
delicate  mucous  membrane  which  lines  the  inside  of 
the  nose.  To  make  the  surface  on  which  the  nerve 
of  smell  is  distributed  as  large  as  possible,  there  is 
set  into  the  nostrils,  against  the  outer  walls,  a  pair 
of  scroll-like  bones.  These  are  the  turbinatcd  bones 
of  the  face.  Over  their  winding  surfaces,  covered 
with  the  mucous  lining,  the  nerve  of  smell  is  spread. 
The  two  small  nasal  bones  unite  the  nose  to  the 


50  ELEMENTARY  PHYSIOLOGY. 

skull  and  keep  it  in  shape.  The  lower  part  of  the 
nose  is  shaped  by  a  frame  of  cartilage,  the  advan- 
tage of  which  over  a  nose-frame  of  solid  bone  you 
can  readily  see. 

Things  which  have  an  odor,  or  smell, 

MM.O^W     \W  O 

Perceive  give  out  little  particles  of  matter,  alto- 
gether invisible.  As  these  float  in  the 
air,  they  are  drawn  into  the  breathing  passages  of 
the  nose  and  mouth  at  every  breath.  Of  course 
those  which  pass  with  the  air  into  the  mouth  can 
make  no  impression  of  smell,  for  there  are  no  nerves 
there  which  are  affected  by  odors.  But  those  which 
pass  into  the  nostrils  strike  upon  the  olfactory  nerve 
branches  which,  as  we  have  seen,  have  their  special 
location  there.  The  mind,  receiving  these  impres- 
sions, recognizes  the  odor,  which  may  be  feeble  or 
strong,  agreeable  or  very  unpleasant. 

The  sense  of  smell  affords  us  protection  in  two 
important  ways.  Its  organ,  the  nose,  is  set  at  the 
very  gates  of  entrance  of  the  air  we  breathe  and  the 
food  we  eat.  So  when  the  air  is  filled  with  putrid 
or  offensive  invisible  matter,  which,  of  course,  would 
make  it  unfit  to  breathe,,  we  are  cautioned  by  the 
sense  of  smell,  and  instinctively  turn  away  and  seek 
a  purer  air  to  breathe.  Likewise,  we  are  often 
warned,  just  in  time,  against  putting  into  the  mouth, 
as  food,  substances  whose  odor  betrays  their  unfit- 
ness  to  be  eaten.  Fortunately  it  is  so  provided  in 
nature  that  poisonous  and  other  harmful  substances 


THE  SPECIAL  SESNES.  51 

have  generally  a  strong  and  peculiar  smell,  although 
this  is  by  no  means  always  the  case. 

THE    SENSE  OF  TASTE. 

The  special  nerves  of  taste  have  their 
The  Tongue,  loop-like  endings  chiefly  in  the  tongue, 

which  is,  consequently,  usually  spoken 
of  as  the  organ  of  taste.  But  these  papillae,  or  end 
expansions  of  the  nerve  of  taste  are  also  distributed 
over  the  walls  of  the  back  part  of  the  mouth.  On 
account  of  the  numerous  little  folds  of  nerve  endings 
on  the  tongue,  this  organ  has  quite  a  velvety  appear- 
ance. Besides  serving  as  the  chief  organ  of  the 
sense  of  taste,  the  tongue  also  aids  in  the  chewing 
of  the  food  and  in  producing  the  sounds  of  speech. 

When  substances  which  have  a  taste  come 
HOW  We      .  . 

Perceive     in  contact  with  the  papillae  or  nerve  loops 

Taste.  Q£  ^e  tongue,  the  impression  is  at  once 
carried  to  the  brain  and  mind.  In  order  that 
such  an  impression  can  be  made  the  substance 
to  be  tasted  must  be  in  a  dissolved  state. 
No  dry  or  solid  substance  can  be  tasted.  So 
-the  mouth  is"  kept  moist,  and,  as  we  shall  learn 
later,  during  the  process  of  eating,  a  large  quantity 
of  saliva  is  thrown  into  the  mouth.  This  dis- 
solves at  least  a  portion  of  the  food  or  substance 
which  is  in  the  mouth,  so  that  its  taste  is  well  per- 
ceived. When  the  mouth  is  dry  from  disease,  or 
from  great  thirst,  food  has  but  little  taste  and  is 
very  unpalatable.  So  when  the  nerves  of  the  tongue 


52 


ELEMENTARY  PHYSIOLOGY. 


are  covered  with  a  strange  coat,  as  iu  disease,  our 
food  does  not  taste  natural. 


WHAT 


WHEBE? 


WHY? 


OUTLINE. 
ORGANS  OF  THE  SPECIAL  SENSES. 

T  Eye— the  organ  of  sight. 

J  Ear — the  organ  of  hearing. 

]  Nose— the  organ  of  smell. 

i_  Tongue — the  organ  of  taste. 

f  Eye — under  arch  of  frontal  bone. 

J  Ear — in  hollow  of  temporal  bone. 

I  Nose — at  entrance  of  air  and  food  passages. 

^  Tongue — lies  on  the  floor  of  the  mouth. 

f  Eye — to  collect  rays  of  light  from  objects  and  pro- 
duce a  picture  or  image  of  such  objects  on  the 
expansion  of  the  nerve  of  sight. 
Ear — to  collect  sound  waves  and  convey  them  to 

the  nerve  of  hearing. 
Nose — to  bring  odorous  matter  in  contact  with  the 

?aerve  of  smell. 

Tongue— to  bring  substances  having  taste  in  con- 
tact with  the  nerve  of  taste. 

QUESTIONS. 

Where  are  the  nerves  of  common  sensation  distributed  ? 

How  many  nerves  of  special  sensation  are  there  ? 

Can  these  nerves  receive  impressions  directly  ? 

What  is  the  special  instrument  of  the  nerve  of  sight"? 

What  is  the  proper  name  of  the  nerve  of  sight  ? 

By  what  only  is  it  impressible  ? 

What  is  the  use  of  the  eye  ? 

How  is  the  eye  protected  by  its  position  ? 

What  other  means  of  protection  are  furnished  it  ? 

What  is  the  use  of  the  lachrymal  or  tear  gland  ? 

Where  is  this  gland  situated  ? 

After  bathing  the  eye,  how  is  that  fluid  drained  away  ? 

What  is  meant  by  "shedding  tears"  ? 

What  conditions  of  mind  and  body  may  cause  this 


THE  SPECIAL  SENSES.  53 

How  many  coats  has  the  eyeball  ? 

What  is  the  nature  of  the  outer  coafc  ? 

What  is  the  cornea  ? 

Is  the  white  coat  of  the  eye  sensitive  ? 

How  do  you  account  for  the  pain  felt  when  a  cinder  lodges 

on  the  eye  ? 

What  is  meant  by  the  eye  being  "  bloodshot  "  ? 
Does  light  enter  the  eye  through  the  white  coat  ? 
Through  what  does  it  enter  ? 
What  is  the  color  of  the  middle  or  choroid  coat  ? 
What  purpose  does  it  serve  in  the  eyeball  ? 
Where  and  what  is  the  iris  ? 
What  gives  the  eye  its  color  ? 
What  is  the  pupil  ? 

How  is  the  pupil  regulated  to  admit  more  or  less  light  ? 
Where  and  what  is  the  retina  ? 

What  is  formed  by  the  eye  on  the  screen  of  the  retina  ? 
What  humor  lies  between  the  cornea  and  iris  ? 
Where  and  what  is  the  crystalline  lens  ? 
What  humor  occupies  the  back  part  of  the  eye  ? 
Which  of  these  parts  is  most  effective  in  collecting  the  light 

on  the  retina  ? 


What  is  the  nerve  of  hearing  called  ? 
By  what  only  is  it  impressible  ? 
What  is  the  work  of  the  ear  ? 
Into  what  parts  is  the  ear  divided  ? 
What  tube  leads  from  the  outer  ear  to  the  "  drum  "  ? 
Describe  the  ear  drum. 
What  is  the  use  of  the  Eustachian  tube  ? 
What  are  the  parts  of  the  inner  ear  ? 
By  what  are  all  sounds  produced  ? 

Describe  the  course  of  sound-waves  from  a  sounding  body 
through  the  ear  to  the  nerve  of  hearing. 


What  is  the  organ  ot  the  sense  of  smell  ? 

What  is  the  name  of  the  nerve  of  smell  ? 

To  what  is  this  nerve  sensitive  ? 

Against  what  does  the  nerve  of  smell  afford  us  protection. 


54  ELEMENTARY  PHYSIOLOGY. 

Where  are  the  extremities  of  the  nerve  of  taste  located  ? 

What  gives  the  tongue  its  velvety  appearance  ? 

Why  are  dry  or  solid  substances  tasteless  ? 

What  provision  is  made  to  make  food  more  perceptible  to 

the  taste  ? 
Why  does  food  have  no  taste  to  us  when  we  are  sick  ? 


THE  CIRCULATORY  SYSTEM. 


Besides  the  material  which  the  body  needs  for  its 
growth,  during  twenty  years  or  more,  it  is  constantly 
exposed  to  wear  and  tear,  and,  consequently,  it  must 
be  supplied  continually  with  material  for  repair.  It 
is  impossible  altogether  to  avoid  the  wearing  out  of 
parts  of  the  body.  Some  of  the  muscles,  like  those 
of  the  heart,  for  example,  are  on  constant  duty. 
Every  contraction  of  a  muscle  destroys  a  part  of  its 
fiber.  The  nervous  system  is  also  constantly  suffer- 
ing wear.  The  slightest  effort  of  body  or  mind  pro- 
duces damage  which  must  be  made  good  to  maintain 
our  strength.  The  simplest  thought  which  occupies 
the  mind  lays  a  tax  on  the  structure  of  the  brain. 
Either  a  wink  or  a  whisper  destroys  muscular  fibers. 
If  even  these  gentle  movements  are  wearng,  how 
great  must  be  the  destruction  throughout  the  body? 
by  labor  which  exercises  vigorously  the  brain  and 
many  muscles. 

So  a  system  of  organs  is  provided  in  the  body, 
whose  work  it  is  to  carry  to  all  parts  a  supply  of 


THE  CIRCULATORY  SYSTEM.  55 

material  as  may  be  needed  for  building  or  repairing. 
This  is  the  circulatory  system.  The  blood  —  a  bright 
red  fluid  with  which  we  are  all  familiar  —  floats  the 
building  material  through  the  channels  and  reser- 
voirs of  the  circulatory  system.  As  the  building  of 
a  house  requires  many  kinds  of  material,  such  as 
wood,  stone,  iron,  glass,  lime,  sand  and  putty,  so  the 
structure  of  the  body  calls  for  materials  suitable  for 
bone,  muscle,  nerve,  hair,  nails,  and  so  on.  All  this 
variety  of  material  is  carried  by  the  blood  in  its 
ceaseless  rounds  through  the  body. 


of  the  organs  and  vessels  of  this  system 

circulatory  are  the  heart,  the  arteries,  the  veins, 
and  the  capillaries.  The  plate  before 
us  shows  the  heart  in  its  position,  and  gives  us  a  very 
good  idea  of  the  manner  in  which  the  arteries  and 
veins  run  to  and  from  every  part  of  the  body.  The 
figures  of  the  right  arm  and  right  leg  are  so  drawn 
by  the  artist  as  to  show  us  chiefly  the  veins  of  these 
limbs,  while  the  figures  of  the  left  arm  and  left  leg 
show  chiefly  the  arteries. 

The  heart  lies  near  the  center  of  the 

•  lit*  Heart. 

chest,  a  little  to  the  left  of  the  middle 
line.  A  man's  heart  is  about  as  large  as  his  fist.  It 
is  a  very  strong  muscular  pump  or  engine  and  does  an 
enormous  amount  of  very  important  work,  as  we  shall 
soon  see.  It  has  four  chambers  —  two  on  each  side. 
The  upper  chamber  of  the  right  side  of  the  heart  is 
called  the  right  auricle  (U)  ;  below  this  (W)  is  the 


56  ELEMENTARY  PHYSIOLOGY. 

right  ventricle.  The  left  auricle  (V)  forms  the 
upper  chamber,  and  the  left  ventricle  (X)  the  lower 
chamber  of  the  left  side  of  the  heart.  The  upper 
and  lower  chambers — that  is,  the  auricles  and  ventri- 
cles— are  separated  by  valves,  whose  important  use 
we  will  learn  when  we  trace  the  course  of  the  blood 
through  the  heart. 

The  arteries  are  the   vessels  which 

The  Arteries.  ,,        ,  -,       n     .       ..  /. 

carry  the  blood  in  its  course  from 
the  heart.  All  the  arteries  which  distribute  bright 
or  pure  blood  from  the  heart  for  the  nourishment  of 
the  body,  are  represented  by  red  vessels  on  the  plate. 
This  large  artery  —  the  pulmonary  artery  (16) — 
carries  dark  or  impure  blood ;  so  it  is  shown  in  blue. 
Of  course  the  arteries  near  the  heart  are  very  much 
larger  blood-channels  than  those  farther  out,  where 
they  divide  as  you  see,  into  very  many  branches. 

The  veins  are  the  vessels  which  gather 
up  the  blood  from  all  parts  of  the  body 
and  carry  it  to  the  heart.  All  the  veins  which  bring 
dark,  impure  blood  to  the  heart  are  represented  by 
blue  vessels  in  the  figure.  This  (31)  large  vein — 
the  pulmonary  vein — carries  pure  blood;  so  it  is 
shown  in  red.  The  veins  near  the  heart  are  very 
much  larger  than  those  which  are  farther  away. 
There  are  valves  in  the  veins  to  prevent  the  blood 
from  flowing  or  setting  back  in  a  wrong  direction. 

The  capillaries  are  very  fine  tubes 

The  Capillaries.  ..  .  ..*      ,, 

connecting    the    arteries    with   the 


THE  CIRCULATORY  SYSTEM.  57 

veins.  Their  name  comes  from  a  Latin  word  which 
means  a  hair.  It  is  difficult  to  imagine  how  numer- 
ous these  little  capillary  blood-vessels  are,  and  bow 
vw^ll  they  are  distributed  to  all  parts  of  the  body. 
You  could  scarcely  prick  your  skin  with  a  needle 
anywhere  without  bringing  some  blood  to  the  sur- 
face ;  you  are  sure  to  pierce  some  capillary  and  cause 
it  to  leak. 

In    the    capillaries    are    the    landing 

Blood  Change 

in  the  places    where    the    little    cargoes   of 

capillaries.  building  material,  which  have  been 
floated  from  the  port  of  the  heart  through  the  arte- 
rial rivers,  are  unloaded  and  distributed  to  the  thou- 
sands of  little  working  cells,  which  are  everywhere 
busy  in  building  or  repairing  the  body.  At  some 
places  material  for  muscle  is  unloaded;  at  others 
material  for  bone,  nerve  or  finger  nail  is  wanted.  In 
exchange  for  this  new  material  which  the  capillaries 
distribute  to  the  body,  they  take  back  from  the  body 
the  material  which  has  become  old,  worn  out,  and 
unfit  for  use.  The  consequence  is  that  the  blood 
which  has  come  from  the  arteries  into  the  capillaries 
red  and  pure,  leaves  them  and  gathers  in  the  veins, 
dark  and  impure.  It  would  be  altogether  unfit  to 
make  another  round  through  the  body  without  being 
purified;  so  the  capillaries  deliver  it  to  the  veins, 
and  these  carry  it  to  the  heart,  which  drives  it  to  the 
lungs — one  of  the  organs  of  another  system — where 
its  worn-out  matter  is  unloaded,  and  it  is  again  made 
fit  to  feed  the  body. 


58  ELEMENTARY  PHYSIOLOGY. 

We  will  now  trace  and  learn  the  circu- 

of^Biood.  lation  or  course  of  the  bl°od  in  the 
body.  This  diagram*  in  the  center  of 
this  plate  will  help  us  clearly  to  understand  it.  Here 
the  heart  (32)  is  laid  open,  showing  its  inner  cham- 
bers and  the  valves  between  them.  This  large  blood- 
vessel (16)  is  one  of  two  great  veins  which  empty 
the  impure  blood  from  the  body  into  the  right 
auricle  of  the  heart.  It  is  called  the  ascending  vena 
cava,  because  it  brings  the  blood  from  parts  below 
the  heart.  Here  (15)  is  the  other  of  these  large 
veins — the  descending  vena  cava,  bringing  the 
impure  blood  from  the  upper  parts.  A  valve  pre- 
vents the  blood  from  going  back  from  the  right  ven- 
tricle into  the  auricle  above.  Here  (21)  is  the 
pulmonary  artery,  which  carries  the  blood  from  the 
right  ventricle  to  the  lungs.  The  blood  is  driven 
through  this  artery  by  the  contraction  of  the  muscle 
of  the  ventricle.  Coming  back  from  the  lungs  to  the 
heart,  the  blood  flows  through  this  (23)  pulmonary 
vein,  which  empties  into  the  left  auricle.  From  here 
it  goes  through  a  valve  into  the  left  ventricle.  Now 
notice  the  thick  muscle  of  the  left  ventricle.  When 
this  strong  muscle  contracts,  the  blood  is  forced  out 
through  this  (24)  great  artery — the  aorta,  which 
branches  out  into  many  arteries  and  then  into  capil- 
laries all  through  the  body.  It  will  be  well  for 
you  to  learn  and  trace  the  course  of  the  blood  in  this 
way:  Coming  impure  from  the  body,  it  flows  into 

*  See  plate  showing  "Formation  and  Circulation  of  the  Blood." 


THE  CIRCULATORY  SYSTEM.  59 

the  right  auricle;  then  through  the  valve  into  the 
right  ventricle;  then  through  the  pulmonary  artery 
to  the  lungs ;  then  through  the  pulmonary  veins  to 
the  left  auricle;  then  through  the  valve  into  the 
left  ventricle;  then  through  the  aorta  into  many 
arteries ;  then  into  the  capillaries ;  then  ihto  the  veins, 

which  return  it  to  the  heart, 

» 

Three  iHvis-  ^nere  are  really  three  divisions  of  the 
ions  of  the  circulatory  system.  The  first  is  the 
course  of  the  blood  from  the  heart 
through  the  body  for  building  and  repair.  The 
second  is  its  course  from  the  heart  through  the  lungs 
for  its  purification.  The  third  is  a  special  course  of 
a  part  of  the  blood  through  the  liver.  This  is 
called  the  portal  circulation.  We  see  here  (18)  how 
several  of  these  prominent  veins  gather  the  impure 
blood  from  these  lower  organs  in  the  body,  and, 
gathering  into  this  (20)  large  vein,  this  blood  is 
thrown  into  the  liver,  where  it  is  partly  purified, 
after  which  it  is  again  collected  by  this  upper  (20) 
hepatic  vein,  which  turns  it,  as  you  see,  into  the  large 
(16)  ascending  vein,  which  goes  to  the  heart. 

Interesting  The   heart   is'    b?    f&F'    the    strongest 

Facts  about  the    muscular    part   of    the   body.       No 

Circulation.  .         .  ,  -,        »    ..  -, 

engine  in  the  world,  of  its  size,  has 
so  much  strength.  It  beats  about  100,000  times  per 
day,  40,000,000  times  per  year,  and  in  the  life-time 
of  an  octogenarian  3,000,000,000  times  without  a 
stop!  Its  impulse  is  not  only  felt  by  its  throbbing 


60  ELEMENTARY  PHYSIOLOGY. 

on  the  walls  of  the  chest;  it  may  be  easily  felt  at 
several  other  points  quite  remote  from  the  heart 
itself,  as,  for  instance,  at  the  temples  or  at  the  wrists. 
These  impulses,  as  felt  at  these  places,  are  called 
the  pulse.  This  index  to  the  rate  of  the  heart's 
action  is  very  convenient  to  the  physician,  since  it 
makes  known  to  him  at  once  any  acceleration,  retard- 
ation or  irregularity  of  the  blood's  circulation. 


Health  of  the  s^eady  an(^  thorough  work  of  the 

circulatory  organs  of  the  circulatory  system  -is 
very  essential  to  life  and  health.  Any 
cause  which  tends  seriously  to  increase  or  diminish 
the  normal  rate  of  the  heart's  action  is  a  thing  to  be 
avoided.  The  ordinary  quickening  of  the  flow  of 
the  blood,  as  in  moderate  exercise  of  the  body,  is 
not  only  harmless,  but  healthful.  Here,  again,  exer- 
cise must  be  commended  as  a  prime  condition  of 
a  healthy  circulation.  Any  part  of  the  body  which, 
from  any  cause  whatever,  remains  comparatively 
unused,  will  not  be  supplied  by  the  circulatory  sys- 
tem with  a  sufficient  quantity  of  pure  blood  to  main- 
tain its  vigor.  Such  a  part  will  therefore  gradually 
wither  and  die.  It  follows  that  we  need  that  kind 
of  exercise  regularly  which  will  call  into  use  all 
parts  of  the  body,  and  thus  prompt  the  flow  of  blood 
into  every  nook  and  corner  of  our  physical  structure. 

OUTLINE. 

THE    CIRCULATORY    SYSTEM. 
(  Central  organ,  the  heart. 
}  Arteries,  blood-vessels  leading  from  the  heart. 


THE  CIRCULATORY  SYSTEM.  61 

Veins,  blood-vessels  leading  to  the  heart. 
Capillaries,  uniting  arteries  and  veins. 
Three  divisions  of  the  circulation: 
From  heart  to  lungs  and  back  to  heart,  for  purifi- 
WHAT?  •{       cation — pulmonary  circulation. 

From  heart  to  body  and  back  to  heart,  for  nutri- 

tion— systemic  circulation. 
From  veins  of  digestive  organs  through  liver,  for 

partial  purification— portal  circulation. 

f  Heart  in  chest,  near  middle. 

WHEBE?  ^  Arteries,  veins  and  capillaries  distributed  through- 
^     out  the  body. 

f  To  carry  pure  blood  to  all  parts  of  the  body. 
„  J  To  gather  up  useless  or  waste  material  and  carry 
'I       it   to   the  organs  which    remove  it    from  the 

(^     system. 

QUESTIONS. 

What  can  you  say  of  the  "  wear  and  tear  "  of  the  body? 

What  is  the  object  of  the  circulatory  system? 

What  is  the  use  of  the  blood? 

What  are  the  organs  and  vessels  of  the  circulation? 

Where  is  the  heart  situated? 

About  how  large  is  the  human  heart? 

Tell  what  you  can  about  its  purpose. 

How  many  chambers  has  the  heart? 

Where  is  the  right  auricle? 

Where  is  the  right  ventricle? 

Where  is  the  left  auricle? 

Where  is  the  left  ventricle? 

What  are  the  arteries? 

What  kind  of  blood  do  the  arteries  usually  carry? 

What  are  the  veins? 

Do  they  usually  carry  pure  or  impure  blood? 

Why  do  the  veins  have  valves? 

What  are  the  capillaries? 


62  ELEMENTARY  PHYSIOLOGY. 

What  changes  in  the  blood  take  place  in  the  capillaries? 
By  what  large  vein  is  the  blood    from    the  lower  body 

brought  to  the  heart? 
By  what  large  vein  is  the  blood  from  the    upper  body 

brought  to  the  heart? 
What  prevents  the  blood  from  flowing  backward  from  the 

ventricle  to  the  auricle? 
What  is  the  work  of  the  pulmonary  artery? 
What  of  the  pulmonary  veins? 
Why  is  the  muscle  of  the  left  heart  extra  strong? 
What  is  the  aorta? 
Now  trace  the  course  of  the  blood,  beginning  where  it  comes 

impure  to  the  right  auricle. 
How  many  divisions  of  the  circulatory  system? 
Why  does  the  heart  send  the  blood  to  the  lungs? 
Why  through  all  parts  of  the  body  ? 

Why  is  a  large  part  of  the  blood  carried  through  the  liver? 
What  is  meant  by  the  pulse? 
What  is  the  effect  of  exercise  on  the  circulation? 
May  exercise  become  too  violent? 
How  is  the  circulation  affected  in  an  unused  part  of  the 

body? 
What  is  the  best  kind  of  exercise? 


THE  RESPIRATORY  SYSTEM. 


We  have  learned  that  the  blood  in  its  course 
through  the  body  is  made  quite  impure  and  needs 
to  be  repeatedly  purified.  For  this  purpose  the 
body  is  furnished  with  the  respiratory  system.  The 
chief  organs  of  this  system  are  the  lungs,  which  lie 
in  the  chest,  close  around  the  heart.  Let  us  get  a 
clear  and  accurate  idea  how  these  important  organs 
are  situated.  ( Turn  to  the  body  manikin. )  Here  is 


THE  RESPIRATORY  SYSTEM.  63 

a  manikin  of  the  body.  We  will  remove  the  outer 
muscles  of  the  chest.  Now,  the  ribs  are  before  us. 
Eemoving  these,  the  contents  of  the  chest  are  shown 
precisely  in  their  natural  places.  These  (8,  9,)  are 
the  lungs.  The  heart  liesQimmediately  under  and 
between  them. 

The  lungs  are  very  spongy  and  light, 
fiie^m!™  °  being  composed  largely  of  air-cells, 

whose  walls  are  very  delicate.  These 
air-cells  are  all  connected  with  tubes  (Turn  to  (25) 
third  section  of  lungs)  and  these  tubes  unite  into 
this  one  large  air-passage  (24)  called  the  trachea 
or  wind-pipe.  In  the  upper  part  of  this  wind-pipe, 
which  comes  close  up  to  the  mouth,  the  instrument 
of  the  voice,  called  the  larynx,  is  situated.  It  is  this 
(21,  22,  23),  enlarged  portion  of  the  trachea.  The 
exact  structure  of  the  larynx  or  voice-organ  is  shown 
by  special  sections  above  the  lungs  in  the  body  mani- 
kin. This  arrangement  of  these  air-passages  reminds 
one  of  an  inverted  tree.  The  larynx  or  voice-organ 
corresponds  to  the  lower  and  thicker  part  of  the  trunk 
of  the  tree ;  the  trachea  to  the  trunk  itself ;  the  branch- 
ing air-tubes  in  the  lungs  to  the  branches  and  twigs, 
and  the  air-cells  to  the  leaves. 

The  pulmonary  artery,  which  brings 
use  of  the  ^e  jmpure  blood  from  the  heart  into 

jL4ii.ii.ir8* 

the  lungs,  branches  out  (18)  into  many 
small  capillary  tubes  which  wind  among  and  around 
these  numerous  air-cells.  When  the  cells  of  the 


64  ELEMENTARY  PHYSIOLOGY. 

lungs  are  filled  with  air,  the  oxygen  of  the  air,  in  a 
wonderful  way,  passes  through  the  wall  of  the  cell 
and -the  wall  of  the  capillary  and  unites  with  the 
blood.  At  the  same  time,  impurities  from  the  blood 
pass  through  capillary  wall  and  cell  wall  into  the 
cells  and  out  through  the  air-passages  with  the 
escaping  breath.  In  this  way  the  blood  is  renewed, 
purified  and  brightened  by  the  life-giving  oxygen, 
and  starts  vigorously  off  on  another  round  through  the 
body. 

Breathing  is  the  act  of  the  body  by 

Breathing.        ^.^  ^  ^^  ^  fiUed   ^.^   ^  ^ 

emptied  again  at  proper  intervals.  This  operation 
is  so  important  and  essential  to  life,  that  it  has  been 
entrusted  to  the  performance  of  muscles  of  the  invol- 
untary kind,  that  is,  such  as  are  not  dependent  on 
the  direction  of  the  mind.  It  is  true,  the  will  may 
interfere  with  the  work  of  these  muscles,  so  that  we 
may  suspend  breathing  to  some  extent.  But  it  is 
Nature's  plan  that  this  work  should  be  committed  to 
faithful  nerve-centers  and  muscles  appointed  for  the 
purpose.  It  is  well  that  this  is  so,  for,  otherwise* 
during  sleep  or  other  unconscious  moments,  when 
the  mind  gives  no  direction  to  the  body,  breathing 
would  stop  and  life  would  end.  Even  when  awake 
and  in  health,  in  this  very  busy  age,  we  might  for- 
get to  breathe. 

The  scientific  name  for  breathing  is 
respiration.  That  act  of  respiration 
which  brings  air  into  the  lungs  is  called 


THE  RESPIRATORY  SYSTEM,  65 

inspiration;  that  which  drives  the  air  from  the 
lungs,  expiration.  There  are  quite  a  number  of 
muscles  concerned  in  these  acts.  When  the  lungs 
are  to  be  filled,  these  muscles  expand  the  walls  of 
the  chest  so  as  to  enlarge  the  space  inside. 
The  air  rushes  in  through  the  mouth,  nose  and  wind- 
pipe, and  fills  %the  cells.  Then  a  reverse  action  is 
produced  by  the  muscles.  The  chest  contracts  and 
the  air  is  forced  out  from  the  lungs  by  the  same  way 
through  which  it  entered,  but  robbed  of  its  oxygen 
and  mixed  with  gases  discharged  from  the  body. 

Between  the  chest  and  abdomen  is  a 
iiTsM "scies!1"  broad  partition  muscle  called  the  dia- 
phragm. This  muscle  is  chiefly  con- 
cerned in  ordinary,  gentle  breathing.  When  the 
lungs  are  to  be  filled,  the  diaphragm  moves  down- 
ward, pressing  upon  the  contents  of  the  abdomen 
and  enlarging  the  cavity  of  the  chest,  giving  the 
lungs  room  for  full  expansion,  provided  the  act  of 
inspiration  is  unrestricted  and  complete.  In  expira- 
tion, the  diaphragm  rises  and  diminishes  the  capac- 
ity of  the  chest,  forcing  the  air  out  of  the  lungs.  In 
forced  breathing,  the  muscles  between  the  ribs, 
called  the  inter-cosfal  muscles  (6,  rib  section],  take  a 
prominent  part.  These  and  other  muscles  also  take 
more  or  less  part  in  ordinary  breathing. 

The  inside  of  the  chest  is  lined  with  a 

delicate  web  called  the  pleura.    This  is 

also  spread  as  a  covering  over  the  lungs.    It  secretes  a 

OK  THJt 

UNIVERSITY 


66  ELEMENTARY  PH  YSIOLOGY. 

watery  fluid  which  keeps  the  walls  of  the  chest  and 
the  surface  of  the  lungs  moist,  and  thus  prevents 
friction  which  would  otherwise  be  produced  in  the 
movement  of  breathing.  The  pleura  is  shown  at  (7 
on  section  of  the  ribs).  An  inflammation  of  this 
membrane  is  called  pleurisy.  When  both  pleura  and 
lungs  are  inflamed  it  is  called  pleura-pneumonia. 


Health  of  the  -^rom  w^a*  we  Bave  learned  of  the 
Respiratory  structure  of  the  chest  and  the  action  of 
the  lungs  in  breathing,  we  can  not  fail 
to  see  that  the  healthy  and  natural  action  of  the  respi- 
ratory system  requires  perfect  freedom  of  motion  or 
expansion  of  every  part  concerned  in  the  vital  act  of 
respiration.  It  is  Nature's  plan  that  every  air  cell 
in  the  lungs  should  perform  its  appointed  part  with 
all  the  rest,  at  every  breath.  If  the  habit  of  breath- 
ing, full  and  deep,  while  the  chest  is  perfectly  free 
to  expand  and  the  body  is  in  erect  or  straight  posi- 
tion, is  well  formed,  every  lung-cell  will  be  filled  at 
each  inspiration.  But  if  the  chest  is  in  any  degree 
restricted  and  compressed,  the  lungs  will  be  but 
partly  filled,  and  many  of  the  air-cells  will  lose  their 
elasticity,  and  finally  become  utterly  useless.  Such 
an  injurious  interference  with  the  natural  expansion 
of  the  chest  may  be  produced  by  habitual  unnatural 
positions  in  sitting  or  walking,  or  by  wearing  the 
clothing  too  tight  about  the  body. 

We  have  learned  that  the  flow  of  blood 
through  the  vessels  of  the  circulatory 


THE  RESPIRATORY  SYSTEM.  67 

organs  is  much  quickened  by  exercise.  So  the  rapid- 
ity of  the  flow  of  the  blood  through  the  lungs  de- 
pends very  much  on  the  degree  of  our  bodily  activity. 
When  we  lie  in  bed,  for  instance,  the  circulation  goes 
on  very  steadily,  and  our  breathing  is  performed 
very  moderately  and  quietly.  But  as  soon  as  we 
arise  and  move  about,  both  the  circulation  and  respi- 
ration are  quickened.  The  more  vigorous  the  activ- 
ity of  the  body  the  more  air  is  drawn  into  the  lungs 
to  purify  the  greater  quantity  of  flowing  blood.  The 
chest  muscles  act  more  strongly  and  every  cell  in  the 
lungs  is  inflated.  All  this  tends  to  produce  pure 
blood  and  active  lungs,  and,  consequently,  good 
health. 

The  quality  or  purity  of  the  air  which 

t^Bre'ath.0*  we  breathe  is  quite  as  important  as  the 
quantity  which  we  inhale.  We  have 
learned  that  the  oxygen,  which  is  one  of  the  elements 
or  gases  which  compose  the  air,  is  taken  from  the 
lung-cells  to  unite  with  the  blood.  This  alone  would 
make  the  breath  which  is  given  out  impure  because 
of  its  having  been  robbed  of  its  oxygen.  But  the  air 
which  is  forced  out  from  the  lungs  is  made  much 
more  impure  by  the  gases  which  come  from  the  im- 
pure blood  of  the  body.  These  gases  escape  from 
the  lungs  at  every  breath.  It  is  plain  that  if  we 
breathe  in  a  close  room  or  in  a  confined  body  of  air, 
every  breath  adds  to  the  degree  of  impurity  of  the 
air,  so  that  the  latter  becomes  more  and  more  unfit 
to  breathe.  It  becomes  unfit  to  sustain  life,  not  only 


68  ELEMENTARY  PHYSIOLOGY 

because  it  is  robbed  of  the  life  supporting  oxygen, 
but  because  one  of  the  gases  which  are  expelled  from 
the  body,  by  the  breath,  acts  like  a  poison  when  it  is 
inhaled  (re-breathed)  again. 

Ventilation  means  the  furnishing  of  the 

Ventilation. 

needed  supply  of  pure  air.     Nothing  is 
more  important  in  the  line  of  hygienic  or  health  pre- 
cepts than  this,  that  we  should  avoid  the  breathing 
of  air  which  has  been  made  impure  by  the  breath. 
To  avoid  this,  it  is  necessary  to  have,  at  all  times, 
a  proper  interchange  between  the  air  of  a  room  and 
the  pure,  free  air  without.     No  person  can  remain 
long  in  a  closed  room  without  being  injured  by  his 
own  breath.     There  must  be  a  place  of  escape  for 
the  impure  air  and  a  place  of  entrance  for  the  pure 
air.     Since  impure   air   rises  toward  the   top  of  a 
room,  it  escapes  best  from  the  opening  of  a  window 
at  the   top,  while  pure  air  enters  best  through  an 
opening   lower   down.     But   without  attempting  to 
describe  any  of  the  numerous  plans  of  ventilation, 
let  this  precept  suffice:    Get  from  the  abundance  of 
pure  air  which  God  has  provided,  as  Etuch  as  you 
can  at  every  breath,  and  avoid,  as  a  poison,  the  inha- 
lation of  impure  air. 

THE    VOICE. 

The  organs  of  the  voice  are  so  closely  connected 
with  the  respiratory  system  that  we  will  give  a 
brief  description  of  them  here. 


THE  RESPIRATORY  SYSTEM.  69 

The  chief  organ  of  the  voice  is  the  larynx. 

This  is  really  an  expansion  of  the  upper 

The  larynx.  ,       „     .  .     ,  ,         .. 

end  of  the  wind-pipe,  as  already  seen. 
The  prominent  point  on  the  front  of  the  neck,  com- 
monly called  "Adam's  apple,"  is  a  part  of  the  larynx. 
The  cartilages  of  which  the  larynx  is  mainly  composed 
form  a  sort  of  box,  along  whose  two  inner  sides  are 
stretched  two  membranous  chords  called  the  vocal 
chords.  These  come  more  or  less  closely  together  at 
the  middle  of  the  larynx,  the  slit  or  chink  between 
them  being  called  the  glottis.  Through  this  glottis 
every  in-going  and  out-going  breath  ordinarily  passes 
silently.  But  when  the  muscles  which  regulate  the 
vocal  chords  tighten  up  these  chords,  while  air  is 
being  expelled  from  the  lungs,  a  sound  is  produced, 
either  high  or  low,  according  to  the  degree  of  ten- 
sion, or  tightness,  to  which  the  vocal  chords  are  drawn. 
If  you  have  learned  to  sing  up  and 
down  the  eight  tones  of  the  musical 
scale,  you  may  easily  perform  an  experi- 
ment on  the  action  of  the  muscles  which  control  the 
tension  of  the  vocal  chords.  Sound  slowly  the  sylla- 
bles up  and  down  the  scale.  You  will  feel  a  change 
in  the  contraction  of  the  larynx  muscles  at  every 
change  of  tone.  Going  up  the  scale,  that  is,  to  a 
higher  and  higher  pitch,  you  will  feel  a  tightening 
action  of  these  muscles:  coming  down  the  scale  to  a 
lower  and  lower  pitch,  an  opposite  effect  will  be  felt. 
The  action  of  the  breath  on  the  vocal 
chords  which  has  just  been  described, 


An  Experi- 
ment. 


70  ELEMENTARY  PHYSIOLOGY. 

produces  vocal  sounds  of  different  pitch.  Their 
loudness  depends  upon  the  degree  of  force  with  which 
the  breath  is  forced  through  the  glottis.  But  this  is 
not  speech.  To  produce  the  articulate  sounds  of 
language,  the  sounds  which  are  made  by  the  vocal 
cords  are  very  much  modified  and  variously  shaped 
by  the  changing  position  of  tongue  and  mouth,  which 
are  produced  in  speaking.  This  is  illustrated  in 
every  word  we  speak,  and  you  will  find  it  to  be  an 
interesting  experiment  to  utter  slowly  the  sounds 
which  compose  some  word,  while  noticing  the  changes 
which  you  make  in  the  position  of  your  mouth  and 
tongue. 

OTTTLINE. 

THE  HESPIRATORY  SYSTEM. 

Lungs,  very  light  and  spongy,  chiefly  composed  of 

air-cells. 

Trachea — commonly  called  wind-pipe. 
Larnyx — upper  part  of  trachea,  and  organ  of  the 
WHAT  '  voice. 

Air-passages  through  mouth  and  nose. 

Chief   respiratory   muscles — the   diaphragm  and 

inter-costal  muscles. 


f  Lungs — in  middle  of  the  chest. 
J  Trachea — between  throat  and  lungs. 
ERE  .   •<  Diaphragm — between  chest  and  abdomen. 
[^  Inter-costal  muscles— between  the  ribs. 

f  To  furnish  oxygen  to  the  blood. 

WHY  /       j  rjiQ   6Xp6i   impurities   which   come  from  venous 
blood. 


THE  RESPIRATORY  SYSTEM.  71 

QUESTIONS. 

What  is  the  use  of  the  respiratory  system  ? 
What  are  the  chief  organs  of  respiration  ? 
Where  are  the  lungs  located  ? 
Describe  their  structure  ? 
What  is  the  trachea  ? 

What  vessel  brings  the  blood  from  the  heart  to  the  lungs  ? 
Tell  what  takes  place  in  the  lungs. 

Is  the  act  of  breathing  performed  by  voluntary  or  involun- 
tary muscles  ? 

Why  is  this  a  wise  provision  ? 

What  is  meant  by  inspiration  ?    Describe  the  process. 
What  is  meant  by  expiration?    Describe  the  process. 
What  is  the  lining  membrane  of  the  chest  called  ? 
What  is  the  benefit  of  full  and  deep  breathing  ? 
What  are  the  consequences  of  cramping  the  chest  ? 
What  is  the  effect  of  exercise  on  the  lungs  ? 
How  is  the  air  made  impure  by  breathing  ? 
Tell  what  you  can  of  the  necessity  of  ventilation. 
Where  are  the  vocal  cords  ? 
How  are  the  sounds  of  the  voice  produced  ? 
How  is  the  pitch  of  the  voice  varied  ? 
How  are  the  louder  tones  produced  ? 
What  other  organs  assist  in  forming  the  sounds  of  speech  ? 


THE  DIGESTIVE  SYSTEM. 


Where  does  the  building  and  repairing  material, 
which  is  delivered  to  all  parts  of  the  body  by  the 
blood,  come  from  ?  How  is  it  prepared  and  how 
does  it  find  its  way  into  the  blood-vessels  of  the  cir- 
culatory system  ?  These  are  some  of  the  physiolog- 
ical queries  which  come  to  us  now. 


72  ELEMENTARY  PHYSIOLOGY. 

The  matter  of  the  body  all  comes  from 

fto^f  JBtort!"*  our  foocL     To  Provide  our  bodies  with 
such  material,  of  good  quality  and  of 

proper  quantity,  ought  to  be  the  main  object  of  our 
eating.  Not  all  of  the  food  matter  which  we  eat  is 
useful  in  the  body.  So  the  means  of  separating  the 
useful  from  the  useless  is  necessary.  Then,  again, 
the  useful  part?  of  our  food  must  be  very  much 
changed  before  they  can  be  used  by  the  building 
cells  of  the  body.  So  the  means  for  its  proper  prep- 
aration must  be  furnished.  The  system  whose  or- 
gans prepare  the  needed  elements  of  tho  food  for 
the  blood,  and  separate  the  useless  from  the  useful 
portion,  is  called  the  digestive  system. 

The  preparation  of  food  material  for 
*^e  blood  requires  many  operations. 
So  the  digestive  system  has  a  greater 
number  of  special  organs  than  any  other  system  of 
the  body.  We  have  seen  how  the  movements  and 
work  of  the  circulatory  organs  depend  upon  the 
strength  and  prompt  action  of  the  muscles  of  the 
heart;  also,  how  the  respiratory  system  depends  upon 
the  muscular  system  in  the  steady  and  proper  action 
of  the  breathing  muscles.  So,  here,  as  we  study  the 
processes  of  the  digestive  system,  we  shall  find  how 
its  work  depends  upon  the  muscles  which  are  assigned 
to  the  duty  of  producing  the  necessary  movements  of 
its  organs.  Even  the  muscles  of  the  arm  and  hand 
perform  the  very  first  act  in  the  process  of  feeding 
the  body,  in  properly  bringing  the  food  to  the  mouth- 


THE  DIGESTIVE  SYSTEM.  73 

The  whole  process  of  preparing  food  material  for  the 
blood  is  called  digestion.  The  first  step,  that  is, 
bringing  the  food  into  the  mouth,  is  called  prehen- 
sion. 

The  second  step  in  digestion  is  masti- 

Teeth  °* the  cation'  This  is  performed  in  the  mouth 
by  the  teeth.  The  mouth  and  the  teeth, 
as  used  in  chewing  or  masticating  the  food,  have 
been  called  the  mill  of  the  body.  The  grinding  in 
this  mill  is  done  by  the  muscles  which  move  the 
jaws  so  as  to  produce  a  cutting,  crushing  or  grind- 
ing effect  upon  the  food  by  the  teeth. 

There   are  thirty-two  teeth  in  the  full 

Teeth*1"  °f  se^  °^  a  grown  Person-  These  are  set 
in  sockets  of  the  upper  and  lower  jaw- 
bones— sixteen  in  each  jaw.  Eight  front  teeth — 
four  in  each  jaw — are  called  incisors,  or  cutting 
teeth.  On  each  side^  of  these  incisors — above  and 
below — is  a  canine  tooth.  The  two  upper  canines 
are  often  called  eye-teeth,  and  the  lower  canines, 
stomach-teeth.  These  twelve  teeth — eight  are  incis- 
ors and  four  canines — separate  or  bite  off  a  proper 
portion  from  the  food  which  is  brought  to  the  mouth. 
Next  to  the  canines  are  two  bicuspids,  on  both  sides 
of  each  jaw.  Bicuspid  means  having  two  roots. 
Then  follow,  as  back  teeth,  three  molars  or  grinders 
on  both  sides  of  each  jaw.  These  twenty  teeth — 
eight  bicuspids  and  twelve  molars — do  the  work  of 
crushing  or  grinding  the  food  to  a  proper  degree  of 
fineness. 


74  ELEMENTARY  PHYSIOLOGY. 


As  we    have    already  learned,  a  tooth 
e  °f 

a  Tooth. 


°f   is  not  a  bone.      It  does  not  belong  to 


the  skeleton.  The  teeth  are  instru- 
ments or  organs  of  the  digestive  system.  The 
structure  of  a  tooth  is  an  interesting  study.  To  help 
us  understand  it,  we  are  provided,  in  the  Anatomical 
Aid,  with  the  means  of  completely  dissecting  —  that 
is,  separating  into  its  parts,  the  structure  of  a  tooth. 
In  the  manikin  of  a  tooth,  the  little  projecting 
ridges  at  the  top  (1)  are  called  tubercles.  The  por- 
tion above  the  gum  (2)  is  called  the  crown.  This 
is  covered  by  a  thin  layer  of  enamel,  the  hardest 
material  in  the  body.  The  tooth  is  mainly  composed 
of  a  substance  called  dentine,  or  ivory  (9).  At  (6) 
and  (7)  the  roots  of  the  tooth  are  shown.  At  (12) 
blood-vessels  and  nerves  are  seen  to  enter  into 
the  tooth.  When  an  opening  occurs  in  the  body  of 
the  tooth,  from  decay,  this  nerve  is  exposed  to  the 
air  and  the  action  of  food  particles,  and  toothache 
is  the  result. 

The  third  step  in  digestion  is  insaliva- 

Work  of  the 

salivary  lion.  Really,  mastication  and  insahva- 
<•  lamis.  £.Qn  are  performed  at  the  same  time. 

While  the  food  is  being  chewed  by  the  teeth,  a  liquid 
is  mixed  with  it  in  the  mouth.  This  liquid  is  spe- 
cially prepared  for  this  purpose,  from  the  blood,  by  a 
number  of  organs  called  salivary  glands.  By  the 
way,  let  us  not  forget  that  all  the  substances  of  the 
body  are  prepared  from  the  blood.  A  gland  is  an 
organ  which  secretes  —  which  means  separates  —  some 


THE  DIGESTIVE  SYSTEM.  75 

special  or  peculiar  substance  from  the  blood.  So, 
one  of  the  glands  of  the  eye  secretes  tears,  and  the 
salivary  glands  secrete  saliva.  Three  pairs  of  these 
glands  are  quite  prominent.  The  largest  pair  is 
just  below  and  in  front  of  the  ears.  The  second  pair, 
in  size,  lies  under  the  jaw-bone,  and  the  third  pair  is 
under  the  tongue.  These  glands,  between  meals, 
furnish  enough  saliva  to  keep  the  mouth  moist.  But 
when  food  is  taken  into  the  mouth  and  chewed,  or 
even  at  sight  of  something  tempting  to  the  taste, 
they  furnish  it  in  great  abundance.  It  not  only 
moistens  the  food  so  that  it  may  be  easily  swallowed, 
but  it  also  begins  the  process  of  changing  the  food 
material. 

The  fourth  step  in  digestion  is   swal- 

Work  of  the 

Pharynx  and  lowing.     This  is  a  much  more  familiar 

Oesophagus.  ig  the  gci_ 


entific  name  for  the  same  act.  When  the  food  has 
been  properly  prepared  in  the  "  mill  of  the  mouth," 
it  is  swallowed,  or  sent  to  the  stomach.  The  cavity 
back  of  the  mouth  is  called  the  pharynx.  Between 
the  pharynx  and  the  stomach  (refer  to  body  manikin) 
is  this  tube  (35)  called  the  oesophagus.  By  the 
action  of  the  muscles  of  the  pharynx  and  the  oesopha- 
gus, the  food  is  moved  into  the  stomach.  This  is 
deglutition. 

We  have  now  traced  the  course  of  the 

$tonia°h  th°    ^ooc^  *n*°  *ne  ma^n  organ  of  digestion  — 

the  stomach.     Here  its  greatest  change 

is  to  be  produced.     The  position  of   the   stomach 


76  ELEMEN TARY  PHYSIOLOGY. 

should  be  well  understood.  Observe  it  carefully  in 
this  manikin  (31).  The  stomach  has  three  coats  or 
walls.  The  outer  coat  is  thin  and  smooth,  and  fitted 
for  the  protection  of  this  organ  in  its  contact  with 
other  organs.  The  inner  coat — called  the  mucous 
wall — contains  many  little  glands  or  cells,  which 
secrete  a  substance  which  is  very  important  in  the 
process  of  digestion.  It  is  called  the  gastric  juice. 

When  food  comes  into  the  stomach  the 


intermixing  is  made  quite  thorough  by 
the  action  of  the  muscles  which  compose  the  middle 
coat  of  the  stomach.  As  long  as  there  is  food 
within  it,  these  muscles  keep  up  a  churning  motion 
of  the  organ.  The  result  of  the  action  of  the  gastric 
juice  is  that  the  food  is  very  much  changed  in  its 
nature  and  appearance.  It  is  now  called  chyme,  and 
the  change  which  has  been  produced  in  the  stomach, 
chymification. 

At  the  right  end  or  discharging  open- 
ing of  the  stomach  is  placed  a  muscular 
valve  called  the  pylorus.  This  name 
means  gate-keeper.  The  pylorus  is  a  door-keeper  of 
the  stomach.  Such  portions  of  the  contents  of  the 
stomach  which  have  been  properly  changed  into 
chyme,  it  allows  to  pass  out,  but  refuses  passage  to 
other  portions.  Much  depends  upon  the  faithfulness 
of  this  pyloric  muscle.  When  from  any  cause  it 
loses  its  power,  or  refuses  to  act,  the  food  escapes 


THE  DIGESTIVE  SYSTEM.  77 

from  the  stomach  before  it  is  prepared  to  enter  the 
intestines,  which  is  a  form  of  indigestion  which  soon 
destroys  life. 

The  Liver,  as  the  manikin  shows,  is  a 
the  i!iver  very  large  organ  overlying  the  stomach. 

It  weighs  from  three  to  four  pounds. 
It  is  both  a  blood-purifying  and  a  secretory  organ. 
As  a  secreting  organ,  it  performs  its  part  in  the 
process  of  digestion  by  furnishing  a  substance  called 
bile,  which  it  sends  through  a  duct  or  tube  into  the 
duodenum,  or  upper  part  of  the  small  intestines, 
where  it  aids  in  further  change  of  the  chyme 
which  has  just  passed  into  the  intestines  from 
the  stomach. 

Back  of  the  stomach  lies  the  pancreas 

^an^eL1.116       (59)'       ™S    °rgan     furnishes     a   fluid 

called  the  pancreatic  juice,  which  is  also 
brought  into  the  duodenum.  The  action  of  the  bile, 
the  pancreatic  fluid  and  the  intestinal  juice,  is  to 
change  the  chyme  into  chyle,  and  to  separate  the 
useless  or  waste  portion  of  the  food.  This  waste 
portion  is  carried  out  of  the  body  by  way  of  the 
intestines,  and  the  useful  portion,  having  undergone 
all  the  processes  of  digestion,  is  now  ready  to  be 
given  to  the  circulatory  system  for  transportation 
to  every  point  of  demand.  How  the  chyle  is  trans- 
ferred from  the  digestive  organs  into  the  blood  will 
be  shown  in  the  next  chapter. 


78  ELEMENTARY  PHYSIOLOGY. 

Perhaps  no  system  of  the  body  is  more 
Health  of  the  *  J 

Digestive        carelessly  or  more    frequently  abused 

than  the  digestive  system.  No  system 
of  the  body  brings  back  upon  the  abusing  offender 
a  severer  penalty  of  discomfort.  Proper  digestion  is 
the  very  first  condition  of  good  health.  Hence  the 
hygienic  principles  referring  to  this  system  should 
be  carefully  learned  and  regarded. 


The  injury   resulting  from  eating  too 

K  Too 
Fast. 


Eating  TOO      £agt  comes  chiefly  from  this,  that  the 


processes  of  mastication  and  insaliva- 
tion  cannot  be  properly  performed.  Unless  the 
food  is  properly  chewed,  and  thoroughly  mixed  with 
saliva,  its  digestion  in  the  stomach  will  be  either 
much  retarded  or  left  incomplete. 


The  capacity  of  the  stomach  is  limited. 

;  Too 
Much. 


Eating?  TOO      If  it  ip  overloaded,  it  can  not  thoroughly 


digest  its  contents.  Besides,  the  gas- 
tric juice  is  also  limited  in  quantity,  and  will  not 
completely  change  into  chyme  more  than  a  proper 
portion. 

Between  the  digestive  operations  of  the 
stomach,  it  needs  intervals  of  rest.  If 
food  is  taken  too  frequently,  it  loses  its 
vigor,  and  soon  fails  to  perform  its  work  in  a  healthy 
manner. 

Some  articles  ofj  food,  though  very 
tempting  to  the  taste,  are  very  "trying  " 
to  the  stomach.  It  is  plain,  that,  if 


=39 


Exercise. 


THE  DIGESTIVE  SYSTEM. 


these  are  too  frequently  eaten,  the  stomach's  action 
will  be  greatly  impaired.  If  eaten  at  all,  they 
should  be  sparingly  mixed  with  more  digestible 
food. 

Gentle  exercise  is  very  helpful  to  diges- 
tion. But  violent  exercise,  either  just 
before  or  after  a  meal,  is  quite  as  injurious.  A 
cheerful  state  of  mind  is  very  helpful  in  keeping  up 
a  healthy  action  of  all  the  digestive  organs. 

OUTLINE. 

THE  DIGESTIVE  ORGANS. 

Teeth—  32  in  full  set. 

Salivary  Glands—  three  pairs. 
;  Muscles  of  Pharynx  and  (Esophagus. 
-j  Stomach. 

Liver. 

Pancreas. 
L  Intestines. 

Teeth  —  in  sockets  of  jaw-bones. 

Salivary  Glands  —  located  about  the  mouth. 

Pharynx   and  oesophagus  —  funnel    and    tube  — 
between  mouth  and  stomach. 

stomach—  under  diaphragm  in  abdomen. 

Liver—  overlying  the  stomach. 

Pancreas—  lying  back  of  the  stomach. 
^  Intestines—  filling  lower  abdomen. 

Teeth-  to  masticate  the  food. 

Salivary  Glands—  to  furnish  saliva. 

Muscles  of  pharynx  and  oesophagus  move  the  food 
from  mouth  to  stomach. 

Stomach—  to  change  food  to  chyme. 

Liver  —  to  furnish  bile. 

Pancreas  —  to  furnish  pancreatic  juice. 

Intestines—  to  complete  the  work  of  digestion  and 
separate  the  chyle  from  the  waste  matter, 


WHAT? 


WHEBE? 


WHY  ? 


80  ELEMENTARY  PHYSIOLOGY. 

QUESTIONS, 

From  what  does  all  the  body  material  come? 

What  processes  are  necessary  to  fit  food  for  body  nourish- 
ment? 

What  is  the  name  of  the  system  which  performs  these  pro- 
cesses? 

What  is  the  first  act  in  the  process? 

What  steps  take  place  in  the  mouth? 

How  many  teeth  in  a  full  set? 

Name  the  different  kinds  of  teeth. 

How  is  the  food  conveyed  from  the  mouth  to  the  stomach? 

Describe  the  work  of  the  stomach. 

By  what  means  is  the  gastric  juice  well  mixed  with  the  food? 

What  is  the  food,  as  it  leaves  the  stomach,  called? 

Describe  the  action  of  the  pylorus. 

What  does  the  liver  furnish  for  the  work  of  digestion? 

What  is  furnished  by  the  pancreas? 

What  is  the  chyle? 

What  are  the  consequences  of  eating  too  fast? 

What  results  from  over-eating? 

What  from  eating  too  often? 

What  from  eating  indigestible  food? 

What  are  the  effects  of  exercise  on  the  digestion? 


THE  ABSORPTIVE  SYSTEM. 


In  previous  lessons  we  have  learned  how  food  is 
prepared  by  the  organs  of  the  digestive  system  and 
reduced  to  a  fluid  state.  Let  us  also  recall  what  we 
have  learned  of  the  circulatory  system;  how  the 
blood  is  constantly  making  the  circuit  of  the  body, 
carrying  food  to  every  tissue. 

The  sixth  plate  of  the  Anatomical  Aid  shows  most 
admirably  all  the  organs  and  parts  concerned  in  the 


THE  ABSORPTIVE  SYSTEM.  81 

two  processes  just  referred  to,  and  a  careful  stu^y 
of  this  plate  will  enable  us  to  understand  their  rela- 
tion to  and  connection  with  each  other.  How,  then, 
does  the  digested  food  get  into  the  circulation? 
What  provision  is  made  for  transferring  it  from  the 
alimentary  canal  to  these  blood-vessels?  To  answer 
these  questions,  we  must  first  study  how  food  is 

absorbed. 

The  food  in  its  liquid  form  must  in  the 

Absorption. 

first  place  be  removed  from  the  stom- 
ach and  the  intestinal  tube.  This  is  accomplished 
by  a  process  called  absorption.  This  work  may  be 
more  easily  comprehended  by  first  referring  to  a 
similar  process  constantly  going  on  in  vegetable 
growths.  Planted  in  good  soil  and  supplied  with 
water,  a  plant  will  send  out  its  small  rootlets,  whose 
little  mouths  will  drink  in  (absorb]  mineral  sub- 
stances from  the  soil  dissolved  by  the  water.  This 
liquid  plant-food  is  carried  by  the  sap  (vegetable- 
blood)  up  the  trunk  or  stem  to  nourish  the  parts  of 
the  plant.  There  is  a  similar  provision  for  taking 
up  the  liquid  food  from  the  alimentary  canal.  There 
are  little  rootlets  provided  for  this  work  whose  action 
resembles  that  of  the  root-fibers  of  the  plant. 

The  inner  wall  or  coating  of  the  small 
vnii8tinal  intestines  has  a  velvety  or  plush-like 

appearance.  This  is  due  to  the  myri- 
ads of  little  hair-like  projections,  which  hang  down 
from  the  inner  walls  and  point  toward  the  center  of 
the  tube.  These  small  cones  or  fingers  are  called  mill. 


82  ELEMENTARY  PHYSIOLOGY. 

They  are  very  numerous,  covering  the  intestinal 
membrane  as  with  a  coat  of  hair.  The  word  signi- 
fies hair-like  bodies.  These  villi,  which  dip  into  the 
liquid  contents  of  the  alimentary  canal,  are  not 
themselves  the  absorbents;  but  they  contain  small 
rootlets  which  take  up  the  food  and  start  it  on  the 
way  toward  the  heart. 

In  each  villus  (singular  of  villi)  there 
TWO  classes    are  two  kinds  of  little  workers  gather- 

of  Absorbents  .  _...  .  .     ,        »    f.       -,  ,., 

in  the  villi.  ing  up  different  kinds  of  food  particles 
from  the  liquid  mass  in  the  intestines. 
These  are  known  as  blood-vessels  and  lacteals,  and 
are  the  starting  points  of  two  different  routes  by 
which  the  food  is  carried  to  the  heart  and  into  the 
circulation. 

The  blood-vessels  or  veins  are  arranged 
veins  in  the    aroun(j  the  center  of  the  villus,  form- 
ing a  sort  of  net- work.     They  all  unite 
and  form  one  large  vein,  plainly  shown  here  on  the 
Aid  (20).     This  vein  is  called  the  portal  vein. 

portal  The  route  by  which  the  blood  and  food 

circulation,  carried  by  the  veins  reach  the  heart 
constitutes  the  portal  circulation,  which  we  will 
now  consider  a  little  more  fully.  The  portal  vein 
(20)  empties  its  contents  into  the  liver  (33)  from 
below,  and  divides  and  subdivides,  finally  forming 
the  capillaries  of  the  liver.  The  structure  of  the 
liver  is  shown  by  the  Aid  at  (18)  (under  microscopic 
structure  of  the  textures).  In  the  liver  an  important 


THE  ABSORPTIVE  SYSTEM.  83 

process  takes  place.  The  bile  is  secreted  from  the 
venous  blood,  and  stored  up  in  the  gall-bladder,  to 
be  used  when  needed  in  the  digestion  of  food.  The 
blood,  after  being  robbed  of  its  bile  and  changed  in 
other  respects  not  well  understood,  is  again  collected 
and  carried  upward  by  the  hepatic  vein  (20)  and 
emptied  into  the  lower  vena  cava  (16),  which  in  turn 
pours  it  into  the  heart,  as  shown  here  by  the  Aid. 
This  completes  the  portal  circulation. 

Now  let  us  go  back  to  the  same  start- 

RouteCCOnd     *n£  P°in^  and  trace  other  portions  of 

the   digested   food   by   another  route; 

but  which  will  ultimately  lead  to  the  same  cavity  of 

the  heart. 

At  this  point  we  should  observe  how  nicely  every 
organ  of  the  body  is  adapted  to  perform  its  own 
specific  work.  The  blood-vessels  spoken  of  under  a 
preceding  head  take  up  from  the  stomach  and  intes- 
tines only  certain  portions  of  their  contents,  to  do 
which,  they  seem  especially  adapted.  Other  portions 
are  absorbed  by  the  lacteals,  which  seem  to  be  par- 
ticularly suited  for  this  purpose. 

Extending  lengthwise  through  the  cen- 

«Te  vim  ln  ter  of  eacn  little  villus>  surrounded  by 
the  meshes  of  the  small  veins  just 
described,  is  a  single  minute  duct  or  rootlet  called  a 
lacteal.  Lac  means  milk,  and  it  is  owing  to  the 
milk-like  appearance  of  their  contents  that  the  term 
lacteal  is  applied  to  these  vessels. 


84  ELEMENTARY  PHYSIOLOGY. 

As  ID  the  case  of  the  blood-vessels, 
Vesse^Tand  wnich  are  the  beginnings  of  the  portal 
Lymphatic  circulation,  so  the  lacteals  unite  and 

finally  form  the  thoracic  duct  (10). 
Just  as  small  creeks  flow  together  and  form  larger 
streams,  so  the  lacteals  form  chyliferous  vessels, 
which  are  shown  here  at  (7)  on  the  Anatomical  Aid. 
These  vessels  carry  the  chyle  absorbed  by  the  lac- 
teals through  numerous  glands  called  lymphatic 
glands  (6),  and  finally  empty  it  into  the  chyle  recep- 
tacle, which  is  seen  here  at  (9). 

The  chyle  receptacle  is  a  sac-like  expan- 

Thorarie  g|ou    Q£   ^    lower    en(J    of    t}ie    tJloracic 

JLPUft. 

duct,  which  is  about  as  large  as  a  slate 
pencil  or  goose  quill.  The  direction  in  which  it 
carries  the  chyle  is  very  plainly  seen  by  referring  to 
the  Aid.  It  passes  upward  in  front  of  the  spinal 
column  and  behind  the  oesophagus  (2).  At  its  upper 
end  it  bends  forward  and  downward,  something  like 
the  crook  of  a  walking  cane,  and  pours  its  contents 
into  the  left  subclavian  vein.  From  this  point  the 
chyle  passes  into  the  innominate  vein  (14),  and  then 
through  the  upper  vena  cava  (15)  into  the  right 
auricle  of  the  heart. 


Thus  we  have  traced  the  different  sub- 
Been  Done. 


What  Has        stances    of   which    the    digestive  food 


is  composed  by  different  routes  to  the 
same  cavity  of  the  heart,  there  to  mingle  with  each 
other,  and  with  the  impure  blood  collected  from  all 


THE  ABSORPTIVE  SYSTEM.  87 

5.  Being  fatty  substance,  it  is  absorbed  chiefly  by 
the  lacteals. 

6.  The  chyliferous  vessels  (7)   carry  it  through 
the  lymphatic  glands  (6)  into  the  chyle  receptacle  (9). 

7.  The  thoracic  duct   (10)    empties  it  into  the 
subclavian  vein  at  11,  by  which  it  reaches  the  right 
auricle  of  the  heart 

8.  From  this  point  the  two  kinds  of  food  travel 
together  toward  the  outposts  of  the  body,  carrying 
nourishment  wherever  needed. 

THE  LYMPHATIC  VESSELS. 

Besides  the  blood  which  is  found  cir- 
culating in  all  parts  of  the  body,  there 
is  another  fluid,  almost  colorless  in  appearance, 
which  is  also  found  widely  distributed  throughout 
the  system.  This  fluid  is  called  lymph,  which  sig- 
nifies transparent  fluid.  In  composition  the  lymph 
closely  resembles  the  plasma  of  the  blood,  and  con- 
tains minute  bodies  or  corpuscles  resembling  the 
white  corpuscles  of  the  blood;  these  are  called 
lymph  globules  or  lymph  corpuscles. 

This  fluid  is  supposed  to  be  mostly 
S'm™0*"  worn-out  materials  gathered  from  all 

parts  of  the  body.  It  consists  probably 
of  portions  of  blood- ingredients  which  have  oozed 
through  the  walls  of  the  arteries,  veins  and  blood- 
capillaries,  together  with  certain  products  of  the 
combustion  which  takes  place  in  the  body.  These  sub- 
stances are  gathered  up  by  tiny  vessels,  and,  after 


88  ELEMENTARY  PHYSIOLOGY. 

being  worked  over  in  a  manner  not  well  understood, 
they  are  capable  of  further  use  in  the  body.  Thus 
we  see  a  wise  economy  in  allowing  nothing  to  go  to 
waste  which  can  in  any  way  be  put  to  further  use. 
This  reminds  us  of  the  economy  practiced  in  sifting 
coal  ashes  taken  from  our  stoves  and  furnaces,  sav- 
ing therefrom  such  partly  burned  coal  as  may  be 
capable  of  giving  off  more  heat  if  put  into  the  fire 
again. 

The  vessels  which  carry  the  lymph  just 
lymphatics  described  are  called  lymphatics.  They 

are  more  delicate  in  their  structure  than 
the  veins  and  arteries  and  permeate  every  part  of  the 
body.  Wherever  blood  capillaries  are  found,  there 
lymph  capillaries  are  also  found,  though  on  account 
of  their  minute  size  they  can  not  be  seen  until  injected 
with  mercury  or  some  colored  fluid.  They  vary  in 
number  with  the  variation  of  the  number  of  blood 
vessels. 

The  functions  of  the  lymphatics  of  the 

system    may   be   regarded    as   similar 


m  of  to  those  of  tiles,  or  drain  pipes,  which 
farmers  so  frequently  lay  in  wet, 
swampy  lands  for  the  purpose  of  carrying  off  the 
surplus  water.  The  water  soaks  into  these  tiles, 
which  carry  it  off  under  ground,  thus  drying  the  field. 
Likewise  the  surplus  fluids  which  collect  in  all  parts 
of  the  body  are  absorbed  by  the  lymphatics  —  the 
drain  pipes  of  the  body  —  which  unite,  forming 
larger  vessel  s,  which  empty  into  the  thoracic  duct,  with 
the  contents  of  which  the  lymph  reaches  the  heart. 


THE  ABSORPTIVE  SYSTEM.  89 

In  all  parts  of  the  system  the  lymphat- 
ics pass  through  small  bodies  called 

phatic  <;  lands. 

lymphatic  glands,  which  vary  in  size 
from  that  of  a  pin-head  to  an  inch  in  diameter.  It 
is  not  definitely  known  what  the  function  of  these 
glands  is;  but  it  is  probable  that  they  renovate  or 
work  over  the  waste  and  surplus  material  brought 
to  them  by  the  lymphatics,  and  that  the  lymph 
globules  originate  in  them.  Whether  this  is  true 
or  not,  there  can  be  no  doubt  that  these  glands  are 
essential  to  health;  because,  when  they  become 
hardened  or  inflamed,  as  is  often  the  case  in  persons 
of  a  scrofulous  tendency,  health  fails  and  the  patient 
grows  thin  and  emaciated,  even  though  his  diet  may 
be  of  the  proper  kind  and  quantity. 

The  lacteals,  which  we  have  considered 

The  Lacteals,  .  m    ' 

a  Part  of  the  in  connection  with  the  absorption  of  the 
cs"  food  from  the  alimentary  canal,  are  a 
part  of  the  lymphatic  system.  They  constitute  that 
portion  which  begins  in  the  villi  of  the  intestines. 
When  the  process  of  digestion  is  completed,  they 
serve  as  drain-pipes,  like  the  lymphatics  in  the  system 
at  large.  Their  special  work,  however,  is  that  in 
connection  with  the  absorption  of  fatty  food  through 
the  walls  of  the  intestines. 

We  have  learned  how  the  blood  "cir- 

TheL,ymphat-       ,    .        „    , 

ics  compared  culates;     how  it  starts  from  the  heart 


e      ,   and  after  making  the  complete  circuit, 

Blood- Vessels.  ' 

is  brought  back  to  the  heart  again.     We 


90  ELEMENTARY  PHYSIOLOGY. 

have  learned  also  that  the  blood-vessels  both  give 
off  tissue-making  substances  and  take  on  waste  and 
worn-out  material,  which  they  carry  away.  In  con- 
trast with  this  the  lymph  does  not  "circulate."  It  is 
carried  toward  the  heart,  where  it  enters  the  life- 
giving  stream — the  blood.  In  the  lymphatic  system 
there  are,  therefore,  no  vessels  to  correspond  with 
arteries.  Again,  the  lymphatics  collect  worn-out  tis- 
sues, etc.,  but  give  nothing  in  return. 

The  work  of  the  lymphatics  is  not  Con- 
Other  Func-  J  .  r 

tions  or  the  fined  to  the  absorption  of  food  from  the 
Lymphatics.  intestineg  an(j  collecting  surplus  and 

waste  materials  from  the  system  in  general.  Certain 
other  phenomena,  all  of  which  are  of  interest  to  us, 
are  due  to  the  absorbing  power  of  these  vessels.  For 
instance,  when  a  poisonous  substance  is  placed  upon 
the  skin  the  lymphatics  at  once  absorb  it  and  carry 
it  into  the  circulation.  The  lymphatics  of  the  lungs 
take  in  the  poison  of  disease  and  diffuse  it  through- 
out the  system.  When  the  appetite  fails  during 
long-continued  illness,  life  is  sustained  by  the  uncon- 
scious consumption  of  one's  own  flesh,  which  is 
absorbed  by  the  lymphatics  and  carried  out  into  the 
circulation. 

In  a  similar  manner,  as  we  will  learn  further  on, 
the  poisonous  nicotine  of  tobacco  is  absorbed  in  the 
lungs  and  the  system  poisoned.  Thus  we  see  that 
these  vessels,  which  are  ever  active,  take  up,  indis- 
criminately, foods,  poisons,  medicines,  or  the  waste 
of  worn-out  material 


THE  ABSORPTIVE  SYSTEM. 


91 


In  concluding  our  consideration  of  the 

Suggestions  *  . 

to  the  absorptive  system,  let  it  be  suggested 

Teacher.  tliat  the  Anatomical  Aid  be  constantly 
referred  to.  In  all  topics  discussed,  it  will  be  an 
Aid  indeed,  and  the  work  be  made  incomparably 

more  effective. 

OUTLINE. 

Food  is  absorbed. 
It  is  conveyed  to  the  circulation. 
WHAT?     -J  Surplus  and  worn-out  tissues  are  collected. 

They  are  renovated  and  prepared  for  use,  and  are 
again  thrown  into  the  blood  to  be  used. 

In  the  walls  of  the  alimentary  canal. 
In  the  system  at  large. 
WHERE?  ^  In  the  tissue  of  the  skin. 
In  the  cells  of  the  lungs. 
Wherever  blood-vessels  are  found. 

WHY?      -|  To  collect  and  transfer  material. 

QUESTIONS. 
What  is  absorption? 
How  do  plants  illustrate  the  manner  in  which  food  is  taken 

from  the  intestines? 

What  is  there  in  plants  to  correspond  with  blood  in  animals? 
What  gives  the  lining  membrane  of  the  intestines  its  smooth, 

velvet-like  appearance  ? 
What  do  the  intestinal  villi  contain  ? 
Describe  their  structure. 
What  is  the  portal  vein  ? 
Trace  the  food  absorbed  by  the  veins,  from  the  intestines  to 

the  heart. 

How  is  the  blood  changed  in  its  passage  through  the  liver  ? 
Where  is  the  hepatic  vein  ?  and  what  is  its  function  ? 
What  are  the  lacteals  ?    What  is  their  function  ? 
Of  what  general  system  are  they  a  part  ? 


9 2  ELEMENTARY  PHYSIOLOGY. 

Through  what  glands  do  they  pass  ?    Into  what  do  they 

empty  ? 

What  is  chyle  ?     Why  are  the  lacteals  so  called  ? 
What  are  the  chyliferous  vessels  ? 
Describe  the  thoracic  duct.     Locate  it. 
What  is  the  chyle  receptacle  ?     Describe  it. 
Explain  assimilation.    Where  does  it  take  place  ? 
Trace  a  mouthful  of  food  from  the  mouth  to  the  tissue  in  the 

body. 

What  is  lymph  ?    What  does  it  resemble  ? 
What  are  1;,  niph  globules  ? 
Explain  the  origin  of  lymph. 
What  vessels  carry  it  ?     Describe  fully  the  action  of  the 

lymphatics. 

With  what  may  they  be  compared  ? 

In  what  respects  do  the  lymphatics  differ  from  the  blood- 
vessels of  the  general  circulation  ? 
What  is  the  difference  between  lymph  and  blood  ? 
Explain  how  the  lymph  vessels  constitute  a  drainage  system 

of  the  body. 

Whither  is  the  lymph  carried  ? 
What  are  lymphatic  glands  ?    Describe  them. 
What  effect  have  they  upon  the  general  health  when  they 

become  diseased  or  hardened  ? 
Why  should  we  be  careful  not  to  touch  poison  ivy  ? 
What  danger  is  there  in  breathing  the  air  of  a  sick  chamber? 
When  a  squirrel  or  other  animal  hibernates,  on  what  does 

it  subsist  ? 
Why  is  medicine  sometimes  injected  under  the  skin,  and 

how  is  it  rendered  effective  ? 
Name  all  the  vessels  which  constitute  parts  of  the  absorptive 

system. 


THE  EXCRETORY  SYSTEM.  93 

THE  EXCRETORY  SYSTEM. 


It  will  be  remembered  that  the  material  collected 
by  the  lymphatics  is  principally  such  as  is  capable 
of  being  worked  over  in  the  little  workshops,  the 
lymphatic  glands,  and  used  again  as  building  mate- 
rial of  the  body. 

There  is,  however,  much  waste  matter  which  can 
not  be  thus  elaborated  for  further  use  in  tissue- 
building;  and  yet  some  of  this  material  is  taken 
from  the  blood  by  organs  adapted  to  this  particular 
purpose,  and  converted  into  substances  essential  to 
some  of  the  vital  processes.  Other  parts  are  fit  for 
nothing  whatever,  and  must  be  expelled  from  the 
system,  because,  if  allowed  to  remain  in  the  blood, 
they  would  not  only  be  useless,  but  an  actual  poison 
to  the  system. 

The  organs  whose  function  it  is  to  take 

The  Excre- 

tory from  the  blood  such  substances  as   can 


^^  ^Q  utilized  again  in  the  body  -build- 
ing process,  but  which  must  either  be  changed  into 
some  other  substance,  or  expelled  from  the  body, 
are  the  lungs,  liver,  kidneys  and  skin.  Each  of 
these  is  suited  to  take  from  the  blood  its  own  kind 
of  impurities,  and  either  elaborate  them  into  some 
usable  substance  or  start  them  in  their  course  lead- 
ing from  the  body  . 


94  ELEMENTARY  PH  YSIOLOGY. 


THE 

The  excretory   functions   of  the  lungs 

Impurities  J 

Thrown  off  (Turn  to  manikin  of  the  body,  8,  9.) 
e  Lungs.  jiave  been  referred  to  under  Respira- 
tion, and  their  structure  there  explained.  The  pure 
air,  taken  into  the  lungs,  gives  up  its  life-giving 
oxygen,  and  in  return  becomes  heavily  loaded  with 
carbon  dioxide,  or,  as  it  is  more  commonly  called, 
carbonic  acid  gas. 

The  chief  of  the  excretions  fcrom  the 
moxide  lungs  is  carbon  dioxide.  It  is  a  re- 

sult of  the  union  of  the  oxygen  of  the 
air  inhaled,  and  carbon  from  the  tissues  of  the  body. 
This  compound  will  not  only  fail  to  support  life, 
but  is  an  actual  poison. 

The  destructive  nature  of  this  gas  is 
illustrated  in  many  ways.  As  for  in- 
stance, if  a  man  goes  down  into  a  well 
and  is  overcome,  becomes  unconscious  and  helpless, 
it  is  this  gas  which  causes  his  condition.  It  is  of 
the  same  kind  as  that  which  is  thrown  off  by  the 
lungs,  is  colorless,  and  is  heavier  than  air,  and  conse- 
quently settles  to  the  floor,  or  into  cellars,  wells,  etc. 
Therefore  it  is  safer  to  sleep  on  a  bed  than  on  the 
floor,  since  this  deadly  gas  settles,  during  the  night, 
on  the  floor. 

As  it  will  not  support  life  in  man  and  animals,  so 
it  will  not  support  combustion,  or  burning.  Hence, 
if  it  should  become  necessary  to  go  down  into  a  well, 


THE  EXCRETORY  SYSTEM.  95 

it  would  be  advisable  to  first  lower  into  it  a  lighted 
candle.  If  the  candle  continues  to  burn,  it  may 
be  concluded  that  the  well  is  sufficiently  free  from 
carbon  dioxide  to  enter  it  with  safety. 

That  the  lungs  expel  a  gas  which  is 
Test  of  the  identical  with  that'  which  collects  in 

i>reuin. 

wells  may  be  illustrated  by  breathing 
into  a  glass  jar,  after  having  held  the  breath  in  the 
lungs  for  some  time.  If  a  lighted  taper  or  wax 
candle  be  lowered  into  the  jar  containing  this 
exhaled  breath,  it  will  go  out,  thus  showing  the 
absence  of  pure  air  and  the  presence  of  carbonic 
oxide.  Again,  to  show  that  other  substances,  such 
as  particles  of  animal  matter,  are  contained  in  air 
once  breathed,  let  the  contents  of  the  lungs  after  a 
full  inspiration  be  breathed  into  a  bottle  and  corked 
up.  The  effete  matter  excreted  with  the  breath  will 
decompose  and  soon  give  off  an  offensive  odor.  Thus 
we  may  understand  the  need  of  ventilation  already 
mentioned.  We  can  understand  how  the  excretions 
from  the  lungs  soon  make  the  air  in  a  closed  roojn 
unfit  for  breathing,  causing  drowsiness  and  headache. 
The  especial  need  of  well- aired  school-rooms  is 
therefore  urged  for  the  consideration  of  teachers 
and  pupils.  Let  pupils  make  the  simple  tests  men- 
tioned and  see  for  themselves  the  importance  of 
proper  ventilation. 

Besides  what  has  already  been  men- 

tioned' the  luns8  take  from  the  blood 

a  watery  vapor  which  is  ordinarily  not 


96  ELEMENTARY  PHYSIOLOGY. 

visible,  but  in  cold  weather  is  condensed  and  collects 
on  the  windows,  or  can  even  be  seen  as  it  comes  with 
the  breath  from  the  nostrils  or  mouth.  It  is  chiefly 
the  vapor  of  alcohol  which  is  expelled  from  the 
lungs  of  a  person  who  has  used  strong  drinks,  and 
his  breath  thus  tells  the  tale  of  his  indulgence.  It 
has  been  carefully  estimated  that  about  one  or  one 
and  one-fourth  pounds  of  water  is  daily  given  off 
with  the  breath  of  a  man. 

THE    LIVER. 

The  liver,  and  its  connection  with  the 
tor "oif^an*"  Process  °^  digestion  and  also  the  portal 

circulation  have  been  spoken  of  else- 
where. But  it  must  also  be  considered  as  an  excre- 
tory organ.  Its  function  is  not  merely  to  secrete 
from  the  blood  a  fluid  needed  in  the  process  of 
digestion,  but  by  so  doing  it  acts  as  a  blood  purifier. 
It  is  a  well  established  fact,  that,  in  case  of  a  diseased 
liver,  when  that  organ  fails  properly  to  perform  its 
work  of  secreting  the  bile,  which  thus  remains  in  the 
blood,  a  disease  known  as  jaundice  ensues,  and,  if 
this  disease  is  hot  checked,  the  person  dies  with 
symptoms  of  poisoning. 

THE  KIDNEYS. 

The  kidneys  are  two  bean-shaped  bodies,  a  little 
more  than  half  as  large  as  the  closed  fist.  They 
are  located  in  the  back  part  of  the  abdominal  cavity, 
one  on  each  side  of  the  spinal  column.  Their  shape, 
size,  appearance,  color  and  structure  are  very 


THE  EXCRETORY  SYSTEM.  97 

plainly  shown  by  the  Anatomical  Aid  (manikin  of 
the  body).  These  dark-colored  little  glands  have  a 
very  important  function  to  perform.  They  cannot 
delegate  their  work  to  any  other  organ  of  the  body, 
as  is  the  case  with  some  of  the  other  glands.  They 
alone  can  perform  the  work  assigned  them.  Hence, 
when  diseased,  their  work  is  not  done,  and  sickness 
ensues. 

The  particular    and  only    work   of  the 

Work  of  the     i  •  i  •  P  111 

Kidneys.  kidneys  is  to  separate  from  the  blood 
brought  to  them,  a  substance  called 
urea.  This  is  a  very  poisonous  matter,  which,  if 
not  removed  from  the  body  by  the  healthy  action  of 
the  kidneys,  will  accumulate,  and  finally  cause 
death. 

The  renal  arteries  (g)  constantly  carry 

The  Kidneys     .  ,  .  ..  V°/  ,  ,        i 

at  work.  to  the  kidneys  a  portion  of  the  blood, 
which  passes  through  the  capillaries  of 
the  kidneys,  as  seen  by  turning  back  the  first  sec- 
tion of  the  right  kidney  of  the  manikin.  The 
blood  is  again  collected  by  the  veins,  and  conveyed 
through  the  renal  vein  (h)  to  the  large  veins  lead- 
ing to  the  heart.  In  the  capillaries  of  the  kidneys 
the  blood  loses  its  watery  part,  which  carries,  in  so- 
lution, impurities  called  urea.  This  watery  fluid 
soaks  through  the  thin  capillary  walls,  is  collected 
and  conveyed  by  two  tubes  (56),  called  ureters,  to 
the  bladder  (57),  whence  it  is  expelled  from  the 
body. 


98  ELEMENTARY  PHYSIOLOGY. 


Difference  be- 


As  has  been    shown,  the  bile,  secreted 

tween  sec-re-   f  rom  the  blood,  is  utilized  in  the  diges- 
tions of  the 
Liver  and         tive      process.       But     the     secretions 

Kidneys.  Q£  ^Q  kidneys  are  poisonous  to  the 
system,  cannot  be  used  in  any  process  whatever, 
hence  must  be  at  once  removed  from  the  system. 
Thus  the  kidneys  are  exclusively  excretory  organs. 


LESSONS  FROM  THE  MICROSCOPE. 


There  are  about  us  myriads  of  wonder- 
ful creations  which  cannot  be  perceived 
by  our  unaided  senses.  Our  sense  of  sight  is  not 
sufficiently  acute  to  see  the  countless  numbers  of 
minute  living  bodies  which  throng  every  drop  of 
water  taken  from  a  pond.  We  can  not  see  the  tiny 
corpuscles  which  float  in  the  blood  and  give  it  its 
color,  just  as  indigo  dissolved  in  water  will  give  it  a 
blue  color.  Many  persons  know  nothing  of  the 
wondrous  beauty  with  which  God  has  clothed  the 
insects  which  swarm  about  us.  With  the  unaided 
eye  we  see  no  beauty  in  the  so-called  dust  which 
covers  the  wings  of  our  moths  and  butterflies.  But, 
when  we  call  to  our  aid  proper  instruments,  made 
for  the  purpose,  the  dust  on  the  •  wings  and  body  of 
the  butterfly  is  at  once  transformed  into  beautifully 
formed  scales,  of  brillian:  rainbow  colors  and  the 
most  perfect  shape  and  structure.  The  instrument 


LESSONS  FROM  THE  MICROSCOPE.  99 

constructed  to  aid  us  in  seeing  things  which  are  too 
small  for  us  to  see  without  this  apparatus  is  the 
microscope.  Its  structure  and  principles  upon  which 
it  operates,  can  not  here  be  explained.  Let  it  be 
sufficient  to  say  that  the  microscope  is  a  combina- 
tion of  glass  lenses  so  arranged  as  to  make  things 
seen  through  it  much  lai-ger.  If  you  take  your 
grandmother's  spectacles  and  hold  them  just  right, 
objects  seen  through  the  glasses  will  appear  larger. 
In  a  similar  way  and  for  a  similar  purpose  the  glasses, 
or  lenses,  of  a  microscope  are  used,  only  that  the 
microscope  makes  a  much  greater  difference  in  the 
apparent  and  real  size  of  objects  seen  through  it. 

MICROSCOPIC  STRUCTURE  OF  THE  TISSUES. 

As  the  minute  scales  of  the  butterfly 
scope  as  an  can  n°t  be  satisfactorily  examined  with- 
Ajd  m  ou^  ^Q  micrOscope,  so  the  proper  and 

successful  study  of  the  different  tissues 
of  the  body  requires  the  aid  of  this  instrument.  And 
since  it  is  not  possible  for  all  pupils  to  have  access 
to  a  microscope,  it  is  fortunate  that  those  who  have 
made  physiology  a  careful  study,  and  have  examined 
the  various  structures  and  tissues  with  great  care, 
have  made  drawings  and  sketches  which  we  may 
study.  Thus  we  have  here  on  the  Aid  a  series  of 
marvelous  paintings,  true  to  nature,  which  we  can 
study  with  even  more  satisfaction  than  if  we  were  to 
prepare  the  specimens  and  look  at  them  through  the 
microscope  ourselves,  We  have  spoken  of  the  body 


100  ELEMENTARY  PHYSIOLOGY. 

as  "the  house  in  which  we  live."  We  may  carry  the 
comparison  a  little  farther  and  consider  the  different 
tissues  as  the  material  used  in  the  body-building, 
where  they  serve  a  purpose  much  like  that  of  sand, 
stone,  lime,  glass,  bricks  and  so  on,  in  the  construc- 
tion of  a  building. 

MICROSCOPIC  STRUCTURE. 

Here  (1)  we  see  the  three  coats  of  the 
(')".  arteries.  The  outer  layer  is  made 
up  of  a  fibrous  matter,  more  or  less 
elastic.  Next  to  it  lies  the  middle  coat,  which 
consists  of  alternating  layers  of  elastic  tissue  and 
muscular  fibers,  and  the  inner  lining  consists  prin- 
cipally of  a  net- work  of  elastic  tissue. 

As  in  the  arteries,  the  veins  under  the 
Vei^sf  (*)  microscope  show  three  distinct  coats, 

but  the  entire  vein  wall  is  much  thin- 
ner than  that  of  the  artery.  Here  at  (2)  the  structure 
of  the  vein  is  shown.  We  see  also  the  valves,  men- 
tioned under  the  circulation,  which  consists  of  pouch- 
like  folds  of  the  inner  coat.  Here  we  see  three 
valves;  but  sometimes  there  are  but  two,  and  even 
one.  From  their  shape'  and  position  you  may  see 
that  they  will  allow  blood  to  pass  through  them  in 
one  direction,  but  not  in  the  other.  Thus,  blood  can 
not  flow  backward,  which,  you  will  perceive,  is  a  very 
wise  provision.  The  shape  of  these  valves  as  shown 
here  will  suggest  the  appropriateness  of  the  name, 
semilunar  valves. 


LESSONS  FROM  THE  MICROSCOPE.          101 

of  capiiia-  At  (3)  we  have  represented  the  net- 
ries  between  WOrk  of  capillaries  which  constitutes 

Arteries 

and  veins  (3).  the  connection  between  the  arteries  and 
veins.  Here  the  outer  and  middle  walls  of  the 
arteries  have  disappeared,  and  only  the  inner  coat 
remains.  The  filtering  process  can  thus  take  place 
with  little  difficulty. 

of  MUCOUS  All  cavities  of  the  body  which  com- 
Membrane  (4.)  municate  directly  or  indirectly  with 
the  outside  surface  are  lined  with  a  soft,  smooth 
membrane  called  the  mucous  membrane.  This  is  a 
continuation  of  the  skin.  At  the  lips,  for  example, 
we  may  see  that  the  skin  merges  into  a  softer  and 
more  sensitive  coat,  the  mucous  membrane.  Here, 
at  (4)  you  may  notice  its  net- work  of  capillaries. 
1.00  ed€a>ii-  At  (5)  we  see  the  capillary  meshes  of 
lariesoftne  the  skin.  Through  their  folds  are 

absorbed  many  substances  which  are 
then  carried  into  the  system,  as  we  learned  under 
Absorption.  The  activity  of  these  capillaries  as 
absorbents  makes  it  possible  for  sailors  to  quench 
thirst  by  spraying  their  garments  with  sea  water 
when  their  supply  of  fresh  water  is  exhausted.  The 
wet  garments  come  in  contact  with  the  skin,  and  the 
moisture  is  absorbed. 

This  (6)  gives  the  eye  an  opportunity 

tinai  vim**)  to  aid  tne  min<l  in  comprehending  the 
outer  structure  of  the  villi.     The  vein 
capillaries  which  take  up  the  digested  food  are  here 
shown. 


102  ELEMENTARY  PHYSIOLOGY. 

Number   (7)   gives   us   a  view  of  the 
thl  JLunss^r).  structure  of  the  lungs.     As  you  know, 


the  lungs  are  composed  chiefly  of  cells 
in  which  the  imparities  are  exchanged  for  fresh 
supplies  of  life-giving  oxygen.  Here  these  cells  and 
blood-capillaries  are  seen. 

capillaries  of  •*•  **e  Par°tid,   the  principal  one  of  the 
the  Parotid     salivary  glands,  is  also  composed  mostly 


r  (8),  «  .„  ,  ,  , 

Brain  (9)  and  °*  a  capillary  net-work,  as  shown  here 
cellular  (g).     At  (9)  we  see  the  capillaries  of 

Tissue  (1O). 

the  brain,  with  red  and  white  corpuscles, 
or  blood-discs,  passing  through  them,  carrying 
nourishment  to  the  brain. 

(10)  shows  how  cells  grow  in  length  and  then 
split  into  .tissue-forming  fibers.  The  cell,  you  will 
remember,  is  the  smallest  possible  part  of  the  body, 
and  is  the  most  important  structure  of  the  system, 
since  all  tissues  and  organs  are  made  up  of  cells,  just 
as  sandstone  is  made  up  of  millions  of  small  grains 
of  sand.  But  sand  is  lifeless,  while,  in  the  living 
body,  life  resides  in  the  cell. 

Under    the   microscope   the   muscular 

Elastic  Tis-     «•',..,  t 

sues  (ii),iius-  fiber  has  the  appearance   as  shown  at 
?S"™£*      (12).     It  consists,  of  course,  of  many 

(12),  and  Bone-  ^        '  J 

Corpuscles  cells  joined  together,  as  will  be  seen 
by  carefully  examining  this  cut.  The 
structure  of  the  bones,  with  their  canals  and  little 
lakes,  through  which  their  nourishment  is  carried,  is 
nicely  shown  at  (13).  Examine  it  carefully,  and 
then  procure,  if  possible,  a  bone  cut  crosswise,  and 
compare. 


LESSONS  FROM  THE  MICROSCOPE.          103 


voluntary  We  ^ave  seen  that  voluntary  muscles 
muscles  (14).  are  made  up  of  bundles  of  fibers.  This 
is  beautifully  shown  here.  We  also  see  the  cross- 
markings,  or  strice,  which  is  a  peculiarity  of  volun- 
tary muscles.  An  examination  of  a  piece  of  cooked 
beef  will  be  helpful  in  connection  with  this  view. 

The  all-important  gastric  juice,  so  much 
needed  in  a  proper  digestion  of  the 
food,  is  secreted  by  glands  of  the 
stomach  wall.  Such  a  gland  is  here  represented  in 
a  very  admirable  manner.  From  the  little  mouths 
here  seen,  exudes  the  gastric  fluid  during  the  pro- 
cess of  digestion. 

At  (16)  and  (17)  are  representations  of 

Xerve  -fibers  v       ' 

of  Brain  (16),  nerve-fibers  of  the  brain.    Their  healthy 
action,  the  abundance  of  their  cells  and 

their   proper    nourishment   largely    determine   our 

mental  capabilities. 

The  hepatic  or  liver  vein,  by  which 
lie-    *^e  blood  is  collected  and  carried  from 

paticvein(i8).the    liver   toward   the   heart,    is   here 

shown  as  passing  through  the  adjacent  liver  sub- 

stance.   The  meshes  of  the  liver  capillaries  are  also 

seen.     In  these  the  bile  is  secreted. 

The    microscopic    appearance    of    the 

Kidney  ,         ,  *   Ai       i  •  i  -     i 

structure  (it>).  structure  or  the  kidneys  is  here  repre- 
sented (19).  The  peculiar  little  cap- 
sules or  balls,  called  Malpighian  Corpuscles,  are  a 
part  of  the  mysterious  organism  provided  for  the 
secretion  of  the  urea  from  the  blood. 


104  ELEMENTARY  PHYSIOLOGY. 


Red  Blood  ^S'  (20)   shows  the  red  corpuscles 

of     the    blood    of    different    animals. 


Blood  consists  of  a  countless  number 
of  solid  bodies  floating  in  a  liquid.  Some  of  these 
solids  are  of  a  red  color,  while  others  are  pale  or 
white.  These  solids  are  called  corpuscles  or  blood- 
discs.  They  vary  also  in  shape  in  different  ani- 
mals. In  man,  the  discs  are  usually  nearly  or  quite 
circular,  though,  when  seen  in  different  positions, 
they  present  different  appearances;  'just  as  a  coin, 
looked  at  perpendicularly  to  its  surface,  looks  cir- 
cular, and,  when  we  look  at  it  edgewise,  seems  of 
an  entirely*  different  shape.  These  wonderful  little 
bodies  are  so  small  that,  of  the  red  discs,  3,500,  laid 
side  by  side,  would  measure  only  an  inch,  and,  if 
placed  one  upon  another,  18,000  would  be  required 
to  make  a  column  of  that  height.  They  usually 
arrange  themselves  in  piles,  and  fit  in  each  other 
like  so  many  saucers  or  butter  plates.  It  is  the 
great  number  of  these  corpuscles  which  gives  blood 
its  color. 

The  structure  of  the  strong  tendons  by 

niter  pi™  which  the  muscles  are  attached  to  the 
Adipose  Tis-  bones,  is  shown  very  plainly  at  (21,. 
As  will  be  seen  here  they  consist  of 
many  longitudinal  fibers.  Number  (22)  shows  us 
how  adipose  cells  appear  under  the  microscope 
(23),  and  gives  us  another  view  of  the  structure  of 
the  bones.  This  is  from  the  ulna  of  the  forearm. 


LESSONS  FROM  THE  MICROSCOPE.          105 

The    mucous    membrane     lining     the 
mouth,  nose  and   other  cavities  com- 
Ceiis  of  Kpi-    municating  with  the  outside,  is  covered 

dermis 


at  (24)  we  have  a  magnified  view  of  these  cells  from 
the  mouth;  at  (25)  we  see,  as  through  a  micro- 
scope, the  cells  of  the  epidermis.  Though  the  worn- 
out  particles  of  the  cr.ticle  can  be  seen  with  the 
naked  eye,  their  peculiar  structure  can  not  bo  thus 
perceived. 

The   choroid  coat  of   the  eye   is   of   a 

Pigment  from 

<;oat  dark  color,  and    absorbs    the  superflu- 
(26).     ous    ^^   brought   into  the  eye.     Its 


color  is  due  to  a  dark  pigment  consisting  of  regu- 
larly formed  six-sided  cells.  Their  shape  is  seen 
at  (26). 

The  bile  is  secreted  in  the  liver  cells, 

Other   Views  •  .  *        i«   «      • 

to  (3  1),      a  microscopic  view  of   which  is   given 


us  at  (28). 

Each  of  the  thirty-one  pairs  of  spinal  nerves  has 
two  branches,  as  seen  from  (29).  The  posterior 
root  has  a  ganglion  of  nerve  matter  which  has  the 
power  of  originating  motion.  (30  and  (31)  show 
us  how  the  different  nerve-cells  appear  when  seen 
through  the  microscope. 

Thus  we  have  afforded  us  a  series  of  views  by  a 
careful  study  of  which  we  may  be  led  to  appreciate 
the  fact  that  we  are  "fearfully  and  wonderfully 
made." 


EFFECTS  OF  ALCOHOL. 

The  principal  organs  of  the  body,  and 
8ound<Body  *^e  func^ons  °^  each,  are  now  quite 

familiar  to  us.  Let  us  now  consider 
briefly  the  necessity  of  guarding  against  anything 
and  everything  which  would  in  any  way  impair  the 
health  of  these  organs,  or  interfere  with  them  in  the 
performance  of  their  work. 

If  a  grain  of  sand  should  find  its  way  into  the 
eye,  inflammation  would  at  once  result;  sight,  the 
function  of  the  eye,  would  be  interrupted.  If,  on 
account  of  some  disease,  the  muscles  of  the  heart 
should  cease  to  contract  and  expand  with  their 
ordinary  regularity,  or  stop  their  action  entirely, 
the  blood  would  cease  to  circulate  and  life  would  end. 
Thus,  the  well-being  of  the  body,  yea,  life  itself, 
depends  upon  the  healthy  action  of  the  various 
organs  which  are  our  servants  in  our  body- house. 

Does  it  not  seem  strange,  then,  that  so 
of  the  manv  thousands  should  still  persist  in 

abusing  their  bodies,  which  are  made 
"in  the  image  of  {heir  Creator"?  Yet  there  are 
such  who  willfully  take  into  their  systems  that 
which  not  only  interferes  with  the  healthy  action  of 
their  bodily  organs,  but  leads  to  certain  death.  More 
than  this,  they  injure  not  only  their  bodies,  but 
destroy  their  mental  faculties,  dethrone  reason, 
bring  misery  and  woe  upon  their  families,  and  fail 
to  accomplish  life's  ends. 


EFFECTS  OF  ALCOHOL.  107 

What  is  strong  drink?  It  is  a  liquid 
strong  Drink.  which  contains  ai^hol  in  large  or  small 

quantity;  and,  if  taken  into  the  system,  will  affect, 
more  or  less,  all  the  organs  and  tissues  of  the  body; 
and,  if  the  quantity  is  sufficient,  will  cause  what  is 
called  drunkenness  or  intoxication. 

It  is  a  liquid  which  in  appearance  can 
what  is  if?*  not  be  distinguished  from  water.  If 

one  vial  be  filled  with  water  and  an- 
other with  alcohol,  at  a  little  distance  it  cannot  be 
told  which  contains  the  water  and  which  the  alcohol. 
But  the  properties  of  the  two  are  remarkably  dif- 
ferent. The  alcohol  has  a  strong  odor,  and  a  hot, 
biting  taste.  A  small  quantity  may  be  placed  in  a 
shallow  dish  and  a  burning  match  held  to  it,  when 
it  will  readily  burn  with  a  pale  flame,  but  giving 
off  much  heat.  If  the  white  (albumen)  of  an  egg 
be  put  in  a  cup,  and  alcohol  poured  on  it,  the  albu- 
men will  soon  become  white,  hard  and  tough,  as  if 
cooked.  In  all  these  and  in  many  other  particulars, 
it  differs  very  much  from  water,  which  it  so  much 
resembles  in  appearance. 

Nearly  all  of  the  grains,  as  wheat,  rye, 
origin?8  barley,  corn  and  rice,  contain  much 

starch.  Corn-starch  is  made  from  corn, 
and  sold  by  the  grocer.  The  starch  of  these  grains 
can,  under  certain  circumstances,  be  converted  into 
sugar,  and  this,  in  turn,  can  be  changed  into  two 
very  different  substances,  carbonic  acid  gas  and 


108  ELEMENTARY  PHYSIOLOGY. 

alcohol.  Thus  alcohol  may  be  made  from  many  sub 
stances.  The  juices  of  all  fruits  contain  the  sugar 
from  which  it  may  be  produced.  From  the  grape, 
currant,  blackberry,  elderberry  and  cherry,  wine 
is  made;  from  apples,  cider  is  pressed;  whisky  is 
made  from  corn,  barley,  rye  and  other  grains;  rum 
is  made  from  molasses  and  sugar  cane.  All  of 
these  contain  alcohol  in  different  quantities. 

If  you  take  an  apple  and   squeeze  out 

Sone?8  °^  ^  ^ie  Ju^ce'  y°u  wiH    have   cider. 

If  this  is  allowed  to  stand  in  the 
warm  open  air,  it  will  very  soon  begin  to  change  its 
nature.  If  watched  closely,  small  bubbles  will  be 
seen  rising  to  the  top  and  escaping.  These  are  bub- 
bles of  carbonic  acid  gas,  one  of  the  products  of  the 
change  of  the  fruit-sugar.  The  other  is  alcohol, 
which  mixes  with  the  liquid.  The  cider  is  now  no 
longer  sweet,  but  contains  alcohol,  is  properly  called 
"hard  cider,"  and  is  a  dangerous  drink.  It  is 
the  escaping  gas  that  makes  cider  sparkle,  and 
beer  foam. 

The  change  of  the  cider,  from  sweet  to 
Fermentation-hard,  or  from  the  harmless  juice  of  the 
apple  to  that  containing  alcohol,  is  called  fermenta- 
tion. All  alcohol  is  the  result  of  the  fermentation 
of  sugar,  or  some  substance  containing  sugar.  The 
apple  juice,  as  soon  as  exposed  to  the  warm  atmos- 
phere, absorbs  from  the  air  a  peculiar  substance 
called  a  ferment,  which  is  something  like  yeast.  It 


EFFECTS  OF  ALCOHOL.  109 

at  once  begins  to  "  worK,"  that  is,  it  begins  to  change 
the  sugar  to  carbonic  acid  gas  and  alcohol.  Thus 
wine  is  made  from  grapes,  currants  and  other  fruits. 
This  kind  of  fermentation  is  called  vinous  fermenta- 
tion. 


If  the  process  of  fermentation  is  allowed 
Fermentation  ^°  continue,  the  hard  cider  and  the  fer- 
mented wine  will  again  change  their 
nature.  If  a  barrel  containing  cider  is  left  in 
the  warm  sun,  with  an  open  bung  (why),  it  first 
changes  its  sugar  into  alcohol.  Additional  ferment 
will  change  the  alcohol  of  the  hard  cider  to  acetic 
acid,  or  cider-vinegar.  This  is  called  acetous  fer- 
mentation. 


Beer  brewers  add  water   to  barley, 
>m 

IJarley. 


and  keep  it  sufficiently  warm  to  cause 


it  to  sprout,  when  the  starch  it  contains 
will  change  to  sugar.  More  heat  is  added,  and  the 
germs  or  young  sprouts  are  killed,  and  the  water 
evaporated.  This  is  now  called  malt,  which  is 
soaked  in  water,  the  sugar  which  it  contains  is  dis- 
solved and  the  sweet  liquid  drained  off.  Yeast  is 
added  to  this  liquid,  to  start  the  process  of  fermen- 
tation, or  change  of  sugar  to  carbonic  acid  gas  and 
alcohol.  It  is  now  called  beer. 

If  a  cold  cup  be  inverted  and  held 

Distillation. 

over  the  spout  of  a  tea-kettle  from 
which  steam  is  escaping,  the  steam  will  be  condensed 
and  gather  in  drops  on  the  inner  surface  of  the  cup. 


110  ELEMENT AE  Y  PHYSIOLOG  Y. 

The  water  is  first  changed  to  vapor  and  this  in 
turn  is  condensed  to  a  liquid  again.  This  is  called 
distillation. 

Now,  if  a  quantity  of  wine  or  hard  cider  be 
placed  in  a  vessel  with  an  opening  something  like 
the  spout  of  a  tea-kettle,  and  heat  applied,  distilla- 
tion will  take  place.  But  alcohol  will  boil,  that  is, 
change  to  vapor,  at  a  temperature  of  173°,  while 
water  requires  212°.  Hence,  the  alcohol  will  be 
vaporized  and  pass  off  as  steam  before  the  watery 
portions  will  have  reached  a  sufficient  temperature. 
Thus,  the  vapor  of  alcohol  can  be  condensed  and 
collected  as  almost  or  quite  pure  alcohol.  But  suffi- 
cient heat  may  be  applied  to  drive  off  some  of  the 
water  with  the  alcohol.  When  about  as  much  water 
is  driven  off  as  alcohol,  the  result  of  the  process  of 
distillation  is  brandy,  whisky  or  rum. 

Thus,  we  have  seen  that  there  are 

Two  Classes 

or  strong         two  kinds,  or  classes,  of  strong  drink, 

the  pernicious  element  in  each  being 
alcohol.  One  kind  is  called  fermented  liquors,  such 
as  wine,  beer,  ale  and  cider,  and  contain  from  three 
to  twenty  per  cent,  of  alcohol.  The  other  kind  is 
known  as  distilled  liquors,  rum,  whisky  and  brandy, 
containing  as  high  as  fifty-five  per  cent,  of  alcohol. 
An  appetite  for  these  liquors  is  the  cause  of  more 
poverty,  unhappiness,  wickedness  and  crime  than  all 
other  causes  combined.  We  will  now  consider  their 
effects  upon  the  human  system, 


EFFECTS  OF  ALCOHOL.  Ill 

EFFECTS   ON   THE   DIGKESTIVE    SYSTEM. 

To  possess  a  healthy  digestion  is  a 
great  blessing.  It  is  essential  to  our 
physical  well-being.  Here  we  have  a 
fine  representation  of  a  healthy  stomach  and  liver. 
(See  Aid.)  The  liver  naturally  lies  across  the 
stomach,  but  here*  it  is  turned  up  to  show  us  the 
healthy  appearance  of  a  stomach  which  has  never 
been  abused  by  that  terrible  destroyer,  alcohol. 

If  taken  in  an  undiluted  form,  alcohol 
"  would  burn  the  mouth  and  throat.  The 
stomach  would  suffer  in  a  similar  way.  But  in  its 
most  diluted  form  it  has  an  irritating  effect  upon 
the  lining  membrane  of  the  stomach  and  intestines. 
Inflammation  tells  the  story  of  the  unnatural  condi- 
tion of  things.  The  gastric  juice  becomes  thick  and 
unfit  for  its  work  in  the  digestive  process.  The 
constant  inflammation  indicates  unnatural  heat,  and 
an  unnatural  thirst  ensues,  which  is  the  probable 
reason  for  the  fact  that  the  more  liquor  a  man  drinks 
the  more  he  wants.  The  quantity  he  drinks  to-day 
will  not  satisfy  him  to-morrow,  since  more  and  more 
will  be  needed  to  counteract  the  ever-increasing 
inflammation. 

This  second  cut  shows  us  plainly  the  early  stages 
of  inflammation.  It  represents,  perhaps,  the  stomach 
of  one  who  has  had  his  first  experience  with  the 
deadly  stuff;  and  yet  how  different  in  appearance 
from  the  stomach  represented  above. 


OF  THP 

UNIVERSITY 


112  ELEMENTARY  PHYSIOLOGY. 

At  the  bottom  of  this  chart  we  see  a 
uiceration.  more  a(jvanced  stage  of  the  difficulty. 
The  blood-vessels  are  very  much  dilated,  and  indi- 
cate that  extraordinary  work  has  devolved  upon  this 
organ.  The  blood-vessels  seem  to  have  lost  their 
power  to  contract  sufficiently  to  expel  the  increased 
amount  of  blood  brought  hither.  And  here  we  see 
the  results  (first  cut,  next  chart),  of  long  continued 
distension  of  the  blood-vessels.  They  have  broken 
and  sores  or  ulcers  are  the  result.  The  stomach  is 
now  no  longer  able  to  perform  its  functions;  the 
food  is  no  longer  properly  digested,  and  as  a  con- 
sequence the  blood  is  impoverished,  and  the  general 
health  has  failed.  All  on  account  of  the  drink-habit 
which  has  now  become  so  firmly  fixed  upon  its  victim 
that  it  is  almost  beyond  human  effort  to  break  loose 
from  it. 

The  faithful  servant  of  the  body,  the 

L,ast  Stages  * ' 

of  Alcohol  stomach,  tries,  from  the  first,  to  adapt 
ins"  itself  to  the  derangements  caused  by 
the  use  of  alcohol  as  a  beverage.  Just  as  the  cuti- 
cle of  the  hand  thickens  and  hardens,  when  we  use 
an  ax  or  shovel,  so  the  stomach,  if  it  is  constantly 
being  irritated  by  the  presence  of  alcohol,  becomes 
thick,  tough  and  unnatural;  and  consequently 
becomes  better  adapted  for  the  purpose  of  a  whisky 
jug,  but  less  for  the  purpose  for  which  it  was 
intended  to  digest  food.  The  blood  vessels  of  the 
stomach,  having  been  dilated  to  their  utmost,  their 
diseased  walls  give  way  and  ugly  ulcers  are  formed. 


THE  EFFECTS  OF  ALCOHOL.  113 

These  canker-like  eruptions  seen  here,  first  eat 
through  the  inner  coat,  then  the  outer  is  attacked 
and  the  painful  sores  cause  great  suffering.  Ulti- 
mately it  can  no  longer  accommodate  itself  to  the 
condition  of  things.  It  gives  up  in  despair.  It  can 
no  longer  retain  and  much  less  digest  food.  Its  con- 
dition and  appearance  is  shown  here  on  the  chart. 
A  long  and  painful  disease  follows,  and  at  last  death 
relieves  the  poor  slave  to  appetite. 

Let  us  observe  right  here,  how  gradual  is  the  pro- 
cess. How  small  and  seemingly  insignificant  the 
beginning.  And  yet  how  certainly  does  the  gratifi- 
cation of  one  thirst  create  the  next.  We  would  all  do 
well  to  accept  as  our  motto:  "  Touch  not,  taste  not, 
handle  not." 

We  have  just  seen  how  alarming  is  the 
effect  of  alcohol  on  the  stomach.     But 
the  liver,  the  healthy  action  of  which 
we   have  found  so  necessary  in  the  food-preparing 
and  blood-purifying  processes,  suffers  fully  as  much 
from  the  use  of  alcoholic  drinks. 

It  is  probable  that  most  of  the  alcohol  taken  into 
the  stomach  is  there  absorbed  and  carried  directly 
to  the  liver  without  passing  into  the  intestines.  A 
proper  secretion  of  the  bile  in  the  liver  demands  that 
the  cellular  structure  of  that  organ  remain  un- 
changed. Alcohol  causes  a  change  of  these  cells  to 
fatty  tissue,  and  an  enlargement  of  the  organ  follows. 
Its  tissues  then  become  lumpy  or  knobbed,  and  pro- 
duces what  is  known  as  u  gin,  or  hobnailed  liver." 


114  ELEMENTARY  PHYSIOLOGY. 

Let  us  compare  its  appearance  under  such  conditions 
as  we  have  it  here  represented,  with  its  looks  when 
in  health,  as  seen  on  a  previous  plate. 

What  is  the  result  of  a  liver  thus  dis- 
eased? The  answer  is  two-fold:  First, 
the  bile  and  liver  sugar  are  not  properly  taken  from 
the  blood,  and  whatever  poisonous  matter  may  be 
contained  in  the  blood  which  should  be  removed 
with  the  bile  must  remain  in  the  system,  and  will 
certainly  prove  destructive  to  health.  In  the  second 
place,  the  digestive  process  is  not  furnished  with 
the  needed  bile,  and  the  work  of  preparing  the  food 
will  be  imperfectly  performed. 

The  effect  of  a  continued  use  of  alcohol 
fhe°Kidnry8.  uPon  the  kidneys  is  much  like  that 
upon  the  liver.  In  the  kidneys  the 
blood  is  constantly  being  filtered,  and  the  poisonous 
urea  is  being  taken  from  it  and  expelled  from  the 
body.  If  the  blood  carries  alcohol  into  the  cells  of 
these  organs  they  will  be  irritated,  inflamed,  and 
sometimes  destroyed.  This  is  known  as  Brighfs 
disease,  though  other  causes  may  lead  to  the  same 
difficulties  and  terminate  in  the  same  disease.  Here 
we  have  a  view  of  a  very  common  derangement  with 
drinkers.  It  is  an  accumulation  of  fat  about  the 
kidneys,  and  may  prove  fatal. 

EFFECTS  ON  THE  NERVOUS  SYSTEM. 

Medical    authorities  tell  us  that    after 

On  the  Brain.  ^  death  Qf  ft  hard  drinkerj  more  a]co_ 

hol  is   found  in   the  tissues  of  the  various  parts  of 


THE  EFFECTS  OF  ALCOHOL.  115 

the  nervous  system  than  any  other  part  of  the  body. 
It  has  been  found  in  sufficient  quantities  in  the  brain 
to  distill  it  from  the  brain  tissue.  Its  abundance  in 
the  nervous  tissue  is  probably  due  to  the  amount  of 
water  which  nerve  tissue  contains,  and  for  which 
alcohol  has  a  remarkable  affinity  or  greed.  As  stated 
elsewhere,  if  alcohol  is  poured  in  a  cup  contain- 
ing the  white  of  an  egg ,  it  will  harden  or  coagulate 
it.  The  tissue  of  the  brain  is  similarly  affected  and 
made  less  sensitive.  This  loss  of  feeling  is  called 
paralysis.  It  also  causes  inflammation  as  seen  here 
in  the  first  plate  of  this  chart.  Compare  the  appear- 
ance of  the  two  hemispheres  of  this  important 
organ,  one  side  represents  the  brain  in  health  and 
the  other  as  affected  by  strong  drink. 

THE  BRAIN  IS  THE  SEAT  OF   THE  MIND. 

If  alcohol  effects  its  tissues  as  we  have 
«><Liieii<-eK.  iearne(j  in  the  preceding  topic,  we  may 

understand  to  some  extent  at  least,  how  the  habitual 
use  of  alcoholic  drinks  causes  temporary  insanity; 
and  men  are  made  silly  in  their  actions,  boastful  in 
conversation  and  unmanly  in  every  respect.  That 
part  of  the  brain  which  controls  the  voluntary  mus- 
cles shows  the  effects  of  stimulants  very  promptly. 
The  hand  trembles  and  shakes  "like  a  leaf."  Walk- 
ing soon  becomes  a  difficult  task.  The  control  of 
the  lips  is  lost  and  a  quivering  is  the  result.  The 
tongue  becomes  ungovernable,  and  the  poor  toper 
becomes  an  object  of  pity,  as  he  staggers  through 


116  ELEMENTARY  PHYSIOLOGY. 

the  streets  no   longer   a  man,  but  a  poor,  degraded 
wretch,  made  so  by  his  appetite  for  drink. 

The    effect  of  alcohol  upon  the   brain 
sometimes  manifests  inself  in  a  degen- 


the  Brain.  eration  of  the  brain  tisssue.  Fat  accu- 
mulates as  a  result  of  frequent  intoxications  and 
the  result  is  known  as  alcoholic  softening,  and  the 
appearance  of  the  brain  in  such  condition  is  showp 
by  the  plate. 

The  last  cut  of  the  stomach  on  the  tem- 
Tremens!  perance  charts  gave  us  a  view  of  that 
organ  of  a  patient  suffering  from  de- 
lirium tremens.  The  Aid  furnishes  us  a  correspond- 
ing view  of  the  brain  of  such  a  patient.  It  is  usually 
supposed  that  this  condition  is  reached  only  after 
years  of  dissipation  and  drunkenness.  Ordinarily  this 
is  true.  But  reliable  medical  authorities  affirm  that 
persons  of  a  particularly  nervous  disposition  are 
sometimes  attacked  by  this  terrible  malady  when  but 
small  quantities  of  intoxicants  are  taken.  Those 
who  indulge  in  strong  drink  are  never  absolutely 
safe.  It  may  attack  them  at  any  time. 

The  victim  of  delirium  tremens  is  in  terrible  fear 
and  anxiety.  His  mind  is  so  completely  disturbed 
and  his  imagination  so  thoroughly  aroused  as  to 
cause  him  to  think  his  best  friends  enemies  who 
would  do  him  harm.  He  sees  horrible  sights  and 
hears  noises  which  alarm  him.  In  his  awful  con- 
dition he  raves  and  tears,  cutting,  tearing  and  biting 
himself  like  a  madman  ;  and  not  unfrequently  dies 


THE  EFFECTS  OF  ALCOHOL.  117 

and  thus  escapes  from  his  agony.  Oh,  that  human 
beings  should  so  abuse  themselves  as  to  bring  them- 
selves into  such  a  condition  ! 

The  same  paralyzing  effect  of  alcohol 
x^rve™*  on  the  brain  of  which  we  made  mention 

in  the  preceding  topics,  is  noticeable 
in  the  nerves.  The  alcohol  takes  up  the  moisture 
in  the  nerve  tissues,  leaving  them  more  or  less  inca- 
pable of  transmitting  sensation.  There  is  on  record 
an  account  of  a  man,  who,  in  his  drunken  stupor, 
burned  his  foot  almost  to  a  crisp  without  becoming 
conscious  enough  to  remove  it  from  the  camp  fire 
into  which  he  had  unconsciously  placed  it.  The 
nerves  were  so  thoroughly  paralyzed  by  alcohol  as 
to  fail  to  transmit  sensation  to  the  brain,  even  if 
that  organ  had  been  in  a  fit  condition  to  receive  the 
intelligence.  The  brain  and  nerve  tissues  are 
among  the  first  substances  of  the  body  to  become 
affected  by  alcohol. 

The  effect  of   alcohol  on  the  heart  is 

more  or  less  indirect-      ft  is  through 


it-ant*  upon  the  affected  nerves  that  its  effect  upon 
the  heart  and  circulation  is  brought 
about.  The  action  of  the  heart  is  governed  by  the 
nerves,  which  act  as  a  sort  of  brake,  thus  preventing 
a  too  violent  action.  Now  when  these  nerves  be- 
come affected  and  lose  their  control  of  the  heart's 
action,  it  will  beat  more  rapidly,  and  also  with 
greater  force.  Thus  the  strain  upon  the  heart  is 
greatly  increased,  while  the  intervals  of  rest  be- 


118  ELEMENTARY  PHYSIOLOGY. 

tween  the  beats  is  diminished,  which  must  be  injuri- 
ous to  that  important  organ.  With  the  increased 
activity  of  the  heart,  comes  an  increased  rapidity 
of  the  flow  of  blood  through  the  blood-vessels- 
The  blood  is  forced  to  the  surface,  which  becomes 
flushed,  and,  if  long  continued,  the  blood-capillaries 
at  the  surface  lose  their  power  of  contraction,  and 
the  drunkard's  nose  is  the  result. 

As  in  the  kidneys,  the  tissue  of  the  heart-walls 
will  degenerate  and  change  to  fat.  A  fatty  coat 
may  run  back  from  about  it,  and  it  is  known  as  fatty 
accumulation.  If  the  use  of  alcohol  is  continued, 
the  heart  will  finally  succumb;  its  fibers  will  become 
relaxed,  its  cavities  become  enlarged,  it  will  entirely 
lose  its  power  to  contract,  and  death  will  ensue  from 
paralysis  of  the  heart 

Sometimes  the  heart  continues  its  efforts  to  expel 
the  blood,  even  when  the  cavities  have  increased 
their  capacity,  and  the  walls  become  thin  and  weak. 
Alcoholic  rupture  is  then  likely  to  occur.  The  effect 
on  the  appearance  of  the  nerves,  eye  and  blood- 
vessels is  shown  on  the  Aid. 

"Without  going  farther  into  the  details 
synopsis.  o£  a]cohol5  and  other  effects  upon  the 
human  system  just  mentioned  in  these  lessons,  let 
us  recall  briefly  what  it  will  not  do,  and  then  resolve 
never  to  use  it  except  as  a  medicine,  and  then  only 
when  directed  to  do  so  by  a  competent  physician. 
Following  are  a  few  of  the  many  facts  concerning 
alcohol,  which  have  so  frequently  been  demonstrated 


THE  EFFECTS  OF  ALCOHOL.  119 

as  to  be  no  longer  questioned: 

WHAT   IT  WILL   NOT   DO. 

1.  Alcohol  is  not  a  food,  hence — 

2.  It  will  not  nourish  the  system. 

3.  It  is  not  assimilated  and  made  a  part  of  the 
body  tissue. 

4.  It  will  not  fortify  against  cold. 

5.  It  will  not  quench  thirst. 

6.  It  will  not  increase  our  powers  of  endurance. 

7.  It  will  not  make  the  nerves  more  steady. 

8.  Its  use  will  not  make  us  more  manly. 

9.  It  will  not  increase  our  mental  powers. 

10.  It  will  in  no  way  benefit  the  system,  except 
as  a  prescribed  medicine. 

11.  It  will  not  prolong  life. 

12.  Its  use  can  in  no  way  add  to  our  good  name 
or  reputation. 

TOBACCO  AND  ITS  EFFECTS. 

The  use  of  tobacco  is  so  prevalent  that  all  know 
what  it  is.  Like  alcohol,  it  does  little  or  nothing  for 
which  its  use  can  be  recommended,  while,  on  the 
other  hand,  there  are  many  reasons  for  which  its  use 
should  be  entirely  avoided. 

It  contains  a  substance  called  nicotine, 

poLao°n0  IS  *  which  is  a  deadl7  poison.     This  poison 

can  be  extracted  from  the  leaves  of  the 

tobacco   plant,   and  is  a  dark-colored    liquid   of   a 

sharp,  biting  taste.     It  has  been  found  that  a  few 


120  ELEMENTARY  PHYSIOLOGY. 

drops  of  this  poison,  placed  on  the  tongue  of  a  dog, 
will  cause  death.  This  nicotine,  extracted  from  the 
tobacco  and  evaporated,  forms  large  parts  of  the 
crust  in  the  bowl  of  an  old  tobacco  pipe. 

Its  use  is  unnatural.  When  first  at- 
<mtheireCt8  tempted,  it  causes  nausea  and  nervous 
Young:.  and  muscular  weakness.  It  is  a  well- 

known  fact  that  it  exerts  a  very  perni- 
cious influence,  particularly  upon  the  young.  It 
prevents  their  physical  and  mental  development;  it 
stunts  their  growth,  and  paves  the  way  for  disease 
in  after  years. 

Injurious  as  tobacco  smoking  (in  its 
common  form)  may  be,  smoking  cigar- 
ettes is  even  more  so.  The  poorest 
kind  of  tobacco  is  often  used  in  making  them,  and 
poisonous  substances  are  added  to  give  them  the 
proper  strength  and  flavor.  Opium,  which  is  used 
in  considerable  quantities  in  this  adulteration,  is 
carried  with  the  smoke  to  the  lungs.  Nicotine,  that 
deadly  poison  found  in  tobacco,  aids  in  the  poison- 
ing process.  In  view  of  the  detrimental  effect  of 
cigarettes,  it  is  not  surprising  that  a  number  of 
States  have  enacted  laws  prohibiting  the  sale  of 
cigarettes  to  young  boys. 

To  show  you  that 'the  mucous  lining  of 
ment.X1  *^e  mouth  and  air  passages  is  sub- 

jected to  a  sort  of  tanning  process,  and 
thus  has  its  ordinary  functions  impaired  by  cigar- 
ette smoking,  a  simple  experiment  may  be  per- 


TOBACCO  AND  ITS  EFFECTS. 

formed.  If  we  take  a  clean  white  cloth  or  handker- 
chief, two  or  three  double,  and  inhale  the  smoke  of 
a  lighted  cigarette,  and  then  force  it  from  the  mouth 
through  the  cloth,  a  brownish  yellow  spot  or  stain 
will  be  found  on  it,  which  consists  of  the  poisonous 
nicotine  and  other  ingredients  contained  in  the 
smoke,  and  mixed  with  the  moisture  of  the  mouth. 
Deposits  of  this  kind  are  made  upon  the  walls  of  the 
air  passages  when  cigarettes  are  smoked,  which 
must  be  injurious. 

The  respiratory  organs  suffer  the  most 
The  Respira-  from  cigarette  smoking.    We  have  here 

tory  Organs. 

HOW  Affected.  (See  Aid.)  a  series  of  views  which  will 
help  us  to  understand  the  nature  of  the 
harm  done,  and,  by  a  careful  study  of  these,  we  may, 
perhaps,  all  be  led  to  the  resolve  never  to  smoke 
cigarettes  or  cigars. 

The  trachea,  or  wind-pipe,  in  health  has  the 
appearance  shown  at  1  and  2;  4  shows  us  how 
it  looks  inside,  and  3  outside,  when  it  has  become 
inflamed  and  irritated  by  the  use  of  cigarettes.  The 
inner  structure  of  the  lungs,  with  its  subdivisions 
of  the  bronchial  tubes  and  air-cells,  in  health,  is 
nicely  represented  at  5.  Here  also  we  see  the 
plump,  full,  well-formed  lung  before  it  has  become 
shriveled  up  by  the  contents  of  the  cigarette  smoke. 
At  6  we  see  the  effects.  The  air  cells  are  filled 
up,  and  the  bronchial  subdivisions  are  almost 
wholly  obstructed  by  nicotine  deposits. 

How,  then,  can  the   blood -purify ing  process   be 


122  ELEMENTARY  PHYSIOLOGY. 

successfully  carried  on    in    such  a  lung  as  is  here 
represented  ? 

Here  in  the  lower  right-hand  corner  of  this  plate 
we  have  a  view  of  what  is  left  of  the  lung  after  years 
of  cigarette  smoking.  Nicotine  has  filled  every  air- 
cell.  Nicotine  had  caused  his  death. 

In  the  opposite  lower  corner  on  the  Aid  is  seen 
a  view  of  what  is  called  smoker's  cancer.  It  usually 
occurs  in  the  throat  and  often  proves  fatal. 

We  have  now  briefly  considered  the 
essential  features  in  the  structure  of 
the  human  body  and  the  principal  functions  of  the 
various  organs.  What  is  beneficial,  as  well  as  what 
is  harmful,  in  its  effects,  has  received  attention. 
With  the  assistance  of  the  Anatomical  Aid,  we  have 
endeavored  to  impress  the  mind  with  some  of  the 
effects  of  alcohol  and  tobacco.  If  now,  by  the  use 
of  this  little  book  in  connection  with  the  Aid,  our 
young  people  may  be  induced  to  study  the  wonder- 
ful mechanism  of  their  bodies,  and  try  to  avoid  that 
which  is  injurious  or  in  any  way  interferes  with 
their  physical  or  mental  well-being,  we  shall  have 
accomplished  our  purpose. 


APPENDIX. 


INDEX 

TO  THE 

COMPLETE  NERVOUS  SYSTEM. 


I.     THE  CKANIAL  AND  SPINAL  SYSTEM. 


No.  Common  Name. 

1  Brain. 

2  Small  Brain. 

3  Tree  of  Life. 

4  Yard's  Bridge. 

5  Three  fold  Nerve. 

6  Abducent  Nerve. 

7  Face  and  Sound  Nerve. 

8  Tongue  and  Pharynx  Nerve. 

9  Willis'  Accessory  Nerve. 

10  Loose  cavity  containing  lung 

and  stomach  nerve  ducts. 

11  Lower  tongue  nerve. 

12  Descending  branches  hypo- 

glossal  nerves. 

13  Cranial  portion  of  the  Spinal 

Cord. 

14  Decussate  pyramid. 

15  Part  of  cervical  spinal  cord. 


Latin  or  Professional  Name. 
Cerebrum. 
Cerebellum. 
Arbor  vitaB. 
Pons  Varolii. 
Nervus  Trigeminas. 
Nervus  abducens. 
Nervus    facialis  et  acousti- 

cus. 
Nervus    glosso-pharyngeus, 

vagus  et  accessorius. 
Nervus  accessorius  Willisii. 
Nervus   vagus  pneumo-gas- 

tricus. 

Nervus  hypoglossus. 
Kami  descendens  nervi  hypo- 

glossi. 
Medulla  oblongata. 

Decussatio  pyramidum. 
Pars  cervicalis  medullas  spi- 
nalis. 


11 


APPENDIX. 


No.  Common  Name. 

16  Part  of  thoracic  spinal  cord. 

17  Bulbous  expansion  at 

end  of  spinal  cord. 

18  Terminal     threads,     spinal 

cord. 

19  Neck  nerves  1. 

20  Neck  nerves  8. 

21  Network  of  neck  nerves. 

22  Network  of  arm  nerves. 

23  Back  bone  nerve  1. 

24  Back  bone  nerve  2. 

25  Nerves  between  ribs. 

26  Loin  nerve  1. 

27  Loin  nerve  5. 

28  Network  of  loin  nerves. 

29  Anterior  crural  nerve. 

30  Hip — abdominal  nerve. 


Jl  Hip — groin  nerve. 

32  Groin  skin  nerve. 

33  Obturator  nerve. 

34  Sacral  nerve  1. 

35  Sacral  nerve  5. 

36  Network  of  sacral  nerves. 

37  Coccyx  nerves. 

38  Sympathetic  nerve. 

39  Upper  cervical  ganglion. 

40  Middle  cervical  ganglion. 

41  Lower  cervical  ganglion. 

42  Thoracic  ganglia. 

43  Loin  ganglia. 

44  Sacral  ganglia. 

45  Coccyx  ganglion. 

46  Connecting     branches      be- 

tween sacral  and  sympa- 
thetic nerves. 


Latin  or  Professional  Name. 
Pars  thoracica  medullae  spi. 
nails. 


Filum  terminals. 

Nervus  cervicalis  1. 

Nervus  cervicalis  8. 

Plexus  cervicalis. 

Plexus  brachialis. 

Nervus  dorsalis  1. 

Nervus  dorsalis  2. 

Nervi  intercostales. 

Nervus  lumbalis  1. 

Nervus  lumbalis  5. 

Plexus  lumbalis. 

Nervus  cruralis  anterior. 

Nervus  ilio  —  hypogas  tri- 
cus  (ramus  exterior  et  in- 
terior). 

Nervus  ilio  inguinalis. 

Nervus  inguino  cutaneous. 

Nervus  obturatorius. 

Nervus  sacralis  1. 

Nervus  sacralis  5. 

Plexus  sacralis. 

Nervi  coccygei. 

Nervus  sympaticus. 

Ganglion  cervicale  superior. 

Ganglion  cervicala  medium. 

Ganglion  cervicale  inferior. 

Ganglia  thoracica. 

Ganglia  lumbalia. 

Ganglia  sacralia. 

Ganglion  coccygeum. 


NERVOUS  SYSTEM. 


iii 


No.  Common  Name. 

47  Sciatic  nerve  (Hip  nerve). 

48  Groin  nerve. 

49  Shoulder  bone  nerves. 

50  Branches  of  skin  and  axle 

nerves. 

51  Arm   skin   nerves,   internal 

posterior. 

52  Arm    skin    nerve,  small  in- 

ternal. 

53  Branches  middle  skin  nerves 

(arm). 

54  Middle  arm  skin  nerve. 

55  Branches  skin  palm  nerves  of 

middle  skin  nerve. 

56  Branches  of  middle    under 

skin  nerve  over  ulna. 

57  Branches  under  skin  nerves, 

overlying  cutaneous  mus- 
cle. 

58  Radial  nerve  branches. 

59  Voluntary  ulna  nerve. 

60  Voluntary  fioger  nerves. 

61  Network  of  arm  pit  nerves. 

62  Middle    nerve,    sending 

branches  to  thumb,  index 
and  middle  finger  and 
radial  side  of  ring  ringer. 

63  Ulna  nerve. 

64  Voluntary  ulna  nerve, 

65  Spiral  muscular  nerve  lying 

against  radius. 

66  External  elbow  joint  nerve. 

67  Superficial  radial  nerve. 

68  Musculo  cutaneus  nerve. 

69  Anterior  leg  nerve. 

70  External    anterior    femoral 

nerve. 


Latin  or  Professional  Name. 
Nervus  ischiadicus. 
Nervus  inguinalis. 
Nervi  supraclaviculares. 
Kami  cutaneus  et  nervi  ax- 

illaris. 
Nervi  cutaue  us  brachii,  in- 

ternus  posterior. 
Nervi  cutaneus  brachii  inter- 

nus  (minor). 
Bamus  nervi  cutanei  medii. 

Nervue     cutaneus     brachii 

medius  v.  internus  major. 
Kamus   cutaneus    palmaris, 

nerv.  cutan.  medii. 
Ramus      outaneus     ulnaris 

nerv.  cutan.  medii. 
Ramus  cutaneous  nerv.  raus- 

culo  cutanei. 

Ramus  nervi  radiales. 
Nervus  ulnaris  volaris. 
Nervus  digitales  volaris. 
Plexus  axillaris  (brachialis). 
Nervus  medianus. 


Nervus  ulnaris. 
Nervus  ulnaris  volaris. 
Nervus  musculo — spiralus  v. 

radialis. 

Nervus  interosseus  externus. 
Nervus  radialis  superficialis. 
Nervus  musculo— cutaneus. 
Nervus  cruralis  anterior. 
Nervus     cutaneus    femoris 

anterior  externa. 


iv 


APPENDIX. 


No.  Common  Name. 

71  Groin  nerve. 

72  Groin  skin  nerve. 

73  Large  saphenic  nerve. 

74  Middle    anterior    femoral 

nerve. 

75  Internal     anterior    femoral 

nerve  lying  against  small 
saphenic. 

76  Branches  of  hip  abdominal 

nerves. 

77  Branches  hip  groin  nerves. 

78  Branches      muscular      leg 

nerves. 

79  Superficial    peroneal    nerve 

fibular. 

80  Internal  foot  skin  nerve. 

81  Middle  foot  skin  nerve. 

82  External  leg  skin  nerve. 

83  Deep    peroneal    or   fibular 

nerve. 

84  Deep     branch   of    peroneal 

nerve. 

85  External  branch  of  peroneal 

nerve. 

86  Cervical  or  neck  back  bone 

joint. 

87  Back  bone  joint  (1). 

88  Back  bone  joint  (12). 

89  Loin  back  bone  joint  (1). 

90  Loin  back  bone  joint  (2). 

91  Sacrum  bone. 

92  Coccyx  bone. 

93  First  rib. 

94  Last  rib. 

95  Crest  of  ilium  bone. 


Latin  or  Professional  Name. 

Nervus  inguinalis. 

Nervus  inguino  cutaneus. 

Nervus  saphenus  major. 

Nervus  cutaneus  femoris 
anterior  mediue. 

Nervus  cutaneus  femoris 
anterior  internus  v.  saphe- 
nus minor. 

Rami  nervi  ilio  hipogastrici. 

Kami  nervi  ilio  inguinalis. 
Eami  musculares  nervi  cru- 

ralis. 
Nervus    peronaeus    superfi- 

cialis,  con. 
Nervus  cutaneus  dorsi  pedis 

internus,  et. 
Nervus  cutaneus  dorsi  pedis 

medius. 
Nervus    cutaneus     c  r  u  r  i  s 

externus. 
Nervus  perouaeus  profundus. 

Eamus   internus    peronaeus 

profundus. 
Bamus  externus  peronseus 

profundus. 
Vertebra  cervici  (7). 

Vertebra  dorsi  (1). 
Vertebra  dorsi  (12). 
Vertebra  lumbalis  (1). 
Vertebra  lumbalis  (2). 
Os  sacrum. 
Os  coccygi. 
Costa  prima. 
Costa  termina. 
Crista  osais  ilii. 


NERVOUS  SYSTEM. 


No.  Common  Name.  Latin  or  Professional  Name. 

96  Underlying    collar     muscle  Musculus     sterno  —  cleido 

connecting  with  dternum.          mastoidens. 

97  Front  scalene  muscle.  Musculus  scalenus  anticus. 

98  Middle  scalene  muscle.  Musculus  scalenus  medins. 

99  Internal  intercostal  muscles.  Musculi  intercostales  inter- 


100  External  intercostal    mus- 

cles. 

101  Square  loin  muscle. 

102  Large  loin  muscle. 

1 03  Internal  iliacal  muscle. 

104  Deltoid  muscle  (shoulder). 

105  Large  breast  muscle. 

106  Flexible  forearm  muscle. 

107  Fold  in  forearm. 
10«  Head  of  ulna. 

109  Aponeuroses  of  the  palm. 

110  Fleshy  ball  of  thumb. 

111  Short  palm  muscle. 

112  Cephalic  vein  (arm). 

113  Basilical  vein. 

114  Middle  basilical  vein. 

115  Middle  cephalic  vein. 

116  Head  of  humeris  bone. 

117  Sharp  process  of  scapula. 

118  Deltoid  muscle. 

119  See  No.  105. 

120  Small  breast  muscle. 

121  Flexible  muscle  of  biceps.- 

122  Short  head  of  biceps  muscl e. 

123  Long  head  of  biceps  muscle. 

124  Coracoid  arm  muscle. 

125  Internal  arm  muscle. 


ni. 

Musculi  intercostales  exter- 

ni. 
Musculus  quadratus  lumbo- 

rum. 

Musculus  psoas  major. 
Musculus  iliacus  internus. 
Musculus  deltoideus. 
Musculus  pectoralis  major. 
Musculus  biceps  flexon  cub- 

iti. 

Plica  cubiti. 
Caput  ulnae. 
Aponeurosis  palmaris. 

Musculus  palmaris  brevis. 
Vena  cephalica  brachii. 
Vena  basilica. 
Vena  median  a  basilica. 
Vena  mediana  cephalica. 
Caput  ossis  humeri. 
Processus  coracoideus. 
Musculus  deltoideus. 

Musculus  pectoralis  minor. 

Musculus  biceps  flexor  cub- 
iti. 

Caput  breve,  musculus  bici- 
pitis. 

Caput  longum,  musculus  bi- 
cipitis. 

Musculus  coraco-brachialis. 

Musculus  interna  brachialis. 


VI 


APPENDIX. 


No.  Common  Name. 

126  Internal  head  of  extending 

triceps  muscle. 

127  Long  head  of  extending  tri- 

ceps muscle. 

128  Muscle,    serving    to    turn 

palm  of  hand  upwards. 

129  Muscle,  long,  round  extend- 

ing wrist. 

130  Muscle,    serving    to    turn 

palm  of  hand  downward. 

131  Round  wrist  muscle  bend- 

ing or  turning. 

132  Short,  like  functions  as  128. 

133  Common     bending    finger 

muscles. 

134  One  of  the  wrist  bending 

muscles. 

135  Long  bending  striking  mus- 

cle. 

136  Muscles  serving  thumb. 

137  Drawing  thumb  to  the  in- 

dex finger. 

138  Shoulder  artery. 

139  Arm  arteries  and  veins. 

Arteries  and  veins  of  uJna. 

142  Upper    anterior    spine    of 

ilium. 

143  Tailor's  muscle. 

144  Middle  gluteal  muscle  (serv- 

ing to  turn  thigh  in  and 
outward). 

145  Deep  leg  stretching  muscle. 

146  Straight  femoral  muscle. 

147  External  vastus  muscle. 

148  Muscle,    serving    to    bring 

thigh  together. 


Latin  or  Professional  Name. 
Caput  internum,  m.  tricipitis 

extensoris. 
Caput  longum  m.   tricipitis 

extensoris. 
Musculus  supinator  longus. 

Musculus     extensor     carpi 

radialis  longus. 
Musculus  pronator  teres. 

Musculus  flexor  carpi  radia- 
lis. 

Musculus  supinator  brevis. 

Musculi  flexores,  digitorum 
communes. 

Musculus  flexor  carpi  ulna- 
ris. 

Musculus  flexor  pollicis 
longus. 

Musculus  abductor  et  flexor 
brevis  pollicis. 

Musculus  abductor  pollicis. 

Arteria  axillaris. 

Arteriae  et  venae  brachialis. 

Arteriae  et  venae  ulnaris. 
Spina  ilii  anterior  superior. 

Musculus  sartorius. 
Musculus  glutaaus  medius. 


Musculus  tensor  faciae  latae. 
Musculus  rectus  femoris. 
Musculus  vastus  externus. 
Musculus  pectinaeus. 


NERVOUS  SYSTEM. 


Vll 


No.  Common  Name. 

149  Long  drawing  muscle. 

150  Large  drawing  muscle. 

151  Leg  muscle. 

152  Internal  vastus  muscle. 

153  Tendon  extending  leg. 

154  Knee. 

155  Shin. 

156  Internal  )  Ankle  joint  pro- 

157  External  J     ject,ions. 
15?  Transverse  ligament. 

159  Foremost  tibial  muscle. 

160  Muscle,  extending  toes  and 

foot. 

161  Long  peroneal  muscle  (Fib- 

ula). 

162  Short  peroneal  muscle. 

163  Long    extending     striking 

foot  muscle. 

164  Counteracting  on  160. 

165  Short  striking  foot  muscle. 

166  Sole  muscle. 

167  Femoral  artery. 

168  Femoral  vein. 

169  Large  saphenic  vein. 


Latin  or  Professional  Name. 
Musculus  abductor  longus. 
Musculus  abductor  magnus. 
Musculus  cruralis. 
Musculus  vastus  internus. 
Tendo  extensorius  cruris. 
Patella. 
Tibia. 

Malleolus  internus. 
Malleolus  externus. 
Ligamentum  transversum. 
Musculus  tibialis  anticus. 
Musculus  extensor  digitor- 

um  pedis  longus. 
Musculus  peronseus  longus. 

Musculus  peronaeus  brevis. 
Musculus   extensor   pollicis 

pedis  longus. 
Musculus  extensor  digitor- 

um  pedis  brevis. 
Musculus   extensor   pollicis 

pedis  brevis. 
Musculus  soleus. 
Arteria  femoralis. 
Vena  femoralis. 
Vena  saphena  magna. 


II.    THE  SYMPATHETIC  SYSTEM. 

DISTRIBUTION  OF  FACIAL  AND  PNETJMOQASTRIO 
NERVES. 


1  Descending  thoracic  aorta.        Aorta  descendens  thoracica. 

2  Innominate  artery.  Arteria  innominata. 

3  Bight  under-shoulder  artery.    Arteria  eubclavia  dextra. 


Vlll 


APPENDIX. 


No.  Common  Name. 

4  Right  carotid  artery. 

5  Internal  carotid  artery. 

6  External  carotid  artery. 

7  Upper  thyroid  artery. 

8  External  jaw  artery. 

9  Occipital  artery. 

10  Upper  ear  artery. 

11  Temporal  artery. 

12  Pulmonary      arteries      and 

veins. 

13  Intercostal  arteries  and  veins. 

14  Descending    aorta    (abdom- 

inal)   with     lower    aortic 
plexus. 

15  Cceliac  artery  and  plexus. 

16  Kidney  artery  and  plexus. 

17  Upper     mesenteric      artery 

with  plexus. 

18  Lower     mesenteric      artery 

with  plexus. 

19  Common  iliacal  artery. 

20  Network  of  upper  abdominal 

nerves. 

21  Network    of    hsemorrhoidal 

nerves. 

22  Network  of  nerves  surround- 

ing bladder. 

23  Network  of  prostate  nerves. 

24  Network  of  lower  abdominal 

nerves. 

25  Lower  phrenic  arteries  with 

network  of  phrenic  nerves. 


Latin  or  Professional  Name. 
Arteria     carotis    communis 

dextra. 

Arteria  carotis  interna. 
Arteria  carotis  externa. 
.  Arteria  thyroidea  sup. 
Arteria  rnaxillaris  externa  (v. 

facialis). 

Arteria  occipitalis. 
Arteria  auricularis  superior. 
Arteria  temporalis. 
Arteriseet  venae  pulmonales. 

Arterise  et  vense  intercostal  is 
Aorta    descendens    abdom- 

inalis,  con  plexus  aorticus 

inferior. 
Arteria  coeliaca  con  plexus 

creliacus. 
Arteria   renalis  con   plexus 

renalis. 
Arteria  mesenterica  superior 

con    plexust  mesentericus 

sup. 
Arteria  mesenterica  inferior 

con    plexus    mesentericus 

inferior. 

Arteria  iliaca  communis. 
Plexus    hypogastricus     su- 
perior. 
Plexus  haemorrhoidales. 

Plexus  vesicalis. 

Plexus  prostaticus. 

Plexus  hypogastricus  in- 
ferior. 

Arterise  phrenicse  inferiores 
con  plexus  phrenicus. 


NERVOUS  SYSTEM. 


IX 


No.  Common  Name. 

26  Great  network  of    stomach 

nerves. 

27  Splenic  artery  with  network 

of  splenic  nerves. 

28  Liver  artery  with  network  of 

liver  nerves. 

29  Upper  network  with   semi- 

lunar  ganglion. 

30  Loin  ganglion. 

31  Sacral  ganglion. 

32  Thoracic  gland  1. 

33  Thoracic  gland  7. 

34  Large  splanchnic  nerve. 

35  Small  splanchnic  nerve. 

36  Upper  network  of  thoracic 

nerves. 

37  Lower    ganglion    of     neck 

nerves. 

38  Middle    ganglion    of    neck 

nerves. 

39  Upper    ganglion     of     neck 

nerves. 

40  Network  of  nerve  molles. 

41  Front  ear  nerve. 

42  Posterior  ear  nerve. 

43  Facial  nerves  and  branches 

causing  goose  flesh  on  skin. 

44  Small  occipital    and  upper 

ear  nerve. 

45  Willis'  accessory  nerve. 

46  Network  of  neck  nerves. 

47  Vagus  nerve. 

48  Recurrent  nerve. 

49  Phrenic  nerve. 

50  Network  of  arm  nerves. 

51  Network  of  loin  nerves. 

52  Network  of  sacral  nerves. 


Latin  or  Professional  Name. 
Plexus  gastricus  magnus. 

Arteria  splenica  con  plexus 

splenicus. 
Arteria  hepatica  con  plexus 

hepaticus. 
Plexus  Solaris  con  ganglion 

semi-lunarius. 
Ganglion  lum  bale. 
Ganglion  sacrale. 
Ganglion  thoracicum  1. 
Ganglion  thoracicum  7. 
Nervus  splanchnicus  major. 
Nervus  splanchnicus  minor. 
Plexus  thoracicus  superior. 

Ganglion  cervicale  inferior. 
Ganglion  cervicale  medina. 
Ganglion  cervicale  superior. 

Plexus  nervorum  mollium. 

Nervus  auricularis  anterior. 

Nervus  auricularis  posterior. 

Nervus  facialis  et  pes  an- 
serius. 

Nervus  occipitalis  minor  ei 
nervus  auricularis  supe- 
rior. 

Nervus  accessorius  Willisii. 

Plexus  cervicales. 

Nervus  vagus. 

Nervus  recurrens. 

Nervus  phrenicue. 

Plexus  brachialis. 

Plexus  lumbalis. 

Plexus  sacralis. 


APPENDIX. 


No.  Common  Name. 

53  Nerves  between  ribs  (inter- 

costal. 

54  Network  of    nerves  of    the 

gullet  (cesophagus.) 

55  Network  of  nerves  of  lungs. 

56  Network  of  nerves  of  phar- 

ynx. 

57  Lower  jawbone. 

58  Hyoid  bone. 

59  Shoulder  bone  or  clavicle. 

60  First  rib. 

61  Second  rib. 

62  Eleventh  rib. 

63  Transverse   process   of   the 

loin  backbone. 

64  Sacrum  bone. 

65  Pubis  bone 

66  Large  cheek  muscle. 

67  Lower  digastric  jaw  muscle. 

68  Chewing  muscle. 

69  Salivary  or  parotid  gland. 

70  Under  jaw  gland. 

71  Sterno-hyoid  muscle. 

72  Foremost  scalene  muscle. 

73  Middle  and  posterior  scal- 

ene muscle. 

74  Midriff. 

75  Square  loin  muscle. 

76  Eight  bronchus. 

77  Kidney. 

78  Upper  kidney  gland. 

79  6ullet. 

80  Stomach. 

8 1  Je  j  un  um  in  testine. 

82  Colon  intestine. 


Latin  or  Professional  Name. 
Nervi  intercostalis. 

Plexus  oesophagens. 

Plexus  pulmonalie. 
Plexus  pharyngens. 

Os  maxillare  inferius. 

Os  hyoides. 

Clavicula. 

Costa  I. 

Costa  II. 

Costa  XT. 

Processus  transversus  verte- 
brae lumbalis. 
Os  sacrum. 
Os  pubis  (symphysis). 
Musculus  zygomanticus 

major. 

Musculus  digaetricus  maxil- 
lae inferioris. 
Musculus  masseter. 
Glandula  parotis. 
Glandula  sub  maxillaris. 
Musculus  sterno-hyoidens. 
Musculus  scalenus  anticus. 
Musculus  scalenus    medius 

et  posticus. 
Diaphragm. 
Musculus   quadratus    lum- 

borum. 

Bronchus  dexter. 
Renes. 

Glandula  supra  renalie. 
(Esophagus. 
Stomachus. 
Intestinum  jejunum. 
Inteetinutn  colon. 


NERVOUS  SYSTEM. 


XI 


No.  Common  Name. 

83    Rectum  intestine. 

81    Bladder. 

8-")    Ureter. 

80    Procumbent  gland. 

S7    Carrying  vessel. 

83    Spermatic  cord. 

89  Internal  spermatic  arteries 
and  veins  with  network 
of  internal  spermatic 
nerves. 


Latin  or  Professional  Name. 

Intestmum  rectum. 

Vesica  urinaria. 

Ureter. 

Gland  ul  a  prostratus. 

Vas  deferens. 

Chorda  spermatica. 

Arteria  et  vena  spermatica 
con  plexus  spermaticus  in- 
tern us. 


III.     THE  SENSE  OF  SMELL. 

VERTICAL  SECTION  OF  NASAL,  CAVITY. 


1  Cavity  in  frontal  bone. 

2  Nasal  bone. 

3  Sphenoidal  cavity. 

4  Cribiform  plate  of  the  eth- 

moidal  bone. 

5  Upper  jawbone. 

6  Incisive  canal. 

7  Hard  palate. 

8  Palate   molles    against  soft 

palate. 

9  Tongue. 

10  Nasal  partition. 

11  Posterior  nasal  cavity. 

12  Roof  of  mouth. 

13  Tonsils. 

14  Pharyngeal  palate  arch. 

15  Olfactory  nerve. 

16  Nasal-palate  nerve  of  soarpa. 

17  Incisive  ganglion. 


Sinus  frontalis  ossie  frontis. 
Os  nasi. 

Sinus  sphenoidalis. 
Lamina  cribrosa  ossis  eth- 

moidea. 

Os  maxillare  superioris. 
Canalis  incivious. 
Palatum  durum. 
Palatum    molle     v.    velum 

palatinum. 
Lingua. 
Septum  nasi. 
Posterior  nares. 
Pharynx. 
Tonsilla. 

Arcus  pharyngo — palatinus. 
Nervus  olfactorius. 
Nervus  naso-palatinus  scar- 

pse. 
Ganglion  incisivum. 


ill 


APPENDIX. 


IV.     THE  SENSE  OF  TASTE. 


NERVES    OF    PALATE    AND    TONGUE. 


No.  Common  Name. 

1  Taste  nerves. 

2  Tongue  and  pharynx  nerve. 

3  Branches  of  three-fold  taste 

nerve. 

4  Branches  of  No.  2. 


5  Upper  lip. 

6  Hard  palate. 

7  Soft  palate. 

8  Uvula. 

9  Side  nerve  of  tongue. 

10  Arch  of  pharynx. 

11  Tonsil. 

12  Entrance  to  gullet. 

13  Root  cf  tongue. 

14  Tongue. 


Latin  or  Professional  Name. 
Nervi  palatini. 
Nervus  glosso-pharyngeus. 
Ramus     gustatorius     nervi 

trigemini. 
Ramus    nervi    glosso-phar- 

yngei  (pro.  m.  glosso-pala- 

tino). 

Labium  superioris. 
Palatum  durum. 
Velum  palatinum  v.  palatum 

raolle. 
Uvula. 

Arcus  glosso-palatinus. 
Arcus  pharyngo-palatinue. 
Tonsilla. 

Isthmus  faucium. 
Radix  lingua. 
Lingua. 


V.     THE  SENSE  OF  SIGHT. 


VERTICAL  SECTION  OF  ORBIT  AND  GLOBE  OF  EYE. 


1  Frontal  bone. 

2  Upper  jawbone. 

3  Fatty  matter. 

4  Frontal  muscle. 

5  Upper  eyelid. 

6  Lower  eyelid. 

7  Lower  oblique  eye  muscle. 

8  Rectal  eye  muscle,  lower. 


Os  frontis. 

Os  maxillare  superius. 

Adipose  tissue. 

Musculus  frontalis. 

Palpebra  superior. 

Palpebra  inferior. 

Musculus  obliquus  oculi 
inferior. 

Musculus  rectus  oculi  in- 
ferior. 


NERVOUS  SYSTEM. 


Xlll 


No.  Common  Name. 

9  Rectal  eye  muscle,  external. 

10  Rectal  eye  muscle,  upper. 

11  Upper  eyelid  muscle. 


12 
13 
14 

15 

16 
17 

18 
19 
20 
21 
22 
23 
24 
25 
26 
27 


Latin  or  Professional  Name. 

Musculus  rectus  oculi,  ex- 
ternus. 

Musculus  rectus  oculi  su- 
perior. 

Musculus  levator  palpebrae 
superior. 

Nervus  opticus. 

CDnjunctiva  palpebrae. 


Eye  nerve. 

Conjunction  of  Eyelids. 

Reflection  of  conjunction  from  inner  surface  of  eyelids  to 

globe. 
Conjunction  of  eyelids  and    Conjunctiva  scleroticse  (bul- 

white  of  eye.  bi.) 

Conjunction  of 'cornea.  Conjunctiva  cornea. 

Strong     horny     membrane    Cornea. 

forming  outer  part  of  eye. 
Membrane  of  aqueous  humor,  lining  anterior  chamber. 


Anterior  camera. 

Posterior  camera. 

Sinus  of  iris. 

Sclerotic  tunic. 

Crystalline  lens. 

Ciliary  body. 

Vitreous  body,  glassy  matter. 

Tunic  of  the  retina. 

Tunic  of  the  choroid. 


Camera  oculi  anterior. 
Camera  oculi  posterior. 
Sinus  venosis  iridis. 
Tunica  sclerotica, 
Lens  crystallina. 
Corpus  ciliare. 
Corpus  vitreum. 
Tunica  retina. 
Tunica  choroidea. 


VI.     THE  SENSE  OF  HEAKING. 


THE    INTERNAL    ORGANS    OF    HEARING    EXPOSED 
WITHOUT  BONY  STRUCTURES. 


1  "External  ear. 

2  Auditory  canal. 

3  Tympanum. 

4  Hammer. 

5  Handle  of  same,  long. 


Auricula  extern  a. 

Meatus  auditor,  externus. 

Membrana  tympani. 

Malleus. 

Processus  longus  mallei. 


XIV 


APPENDIX. 


No.  Common  Name. 

6  Mannubrium  of  hammer. 

7  Anvil. 

8  Short  process  of  same. 

9  Long  process  of  same. 

10  Orbicular  ossicle. 

11  Stapes. 

12  Vestibule. 

13  Upper  semicircular  canal. 

14  Posterior  semicircular  canal. 

15  Lower  semicircular  canal. 

16  Shell,  spiral  cavity. 

17  Cupok  of  shell. 


Latin  or  Professional  Name. 

Mannubrium  mallei. 

Incus. 

Processus  brevis  incudis. 

Proceesus  longus  incudis. 

Ossiculum  orbiculare  Silvii. 

Stapes. 

Vestibulum. 

Canalis  semicircularis  su- 
perior. 

Canalis  semicircularis  pos- 
terior. 

Canalis  semicircularis  in- 
ferior. 

Cochlea. 

Cupola  cochleae. 


No.  336. 

DIXON'S 

COLORED  CRAYONS 

FOR 

MAP  DRAWING. 

ONE  EACH  OF 


IGHT  BLUE. 

BROWN. 
GREEN. 

YELLOW. 
DARK  BLUE. 

RED. 

Jos  Dixon  Crucible  Co. 


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